Characteristics of Korean phonology: Review, tutorial, and case
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Journal of Communication Disorders 42 (2009) 163–179
Tutorial Paper
Characteristics of Korean phonology: Review, tutorial, and case studies of Korean children speaking English
Seunghee Ha a,*, Cynthia J. Johnson b, David P. Kuehn b
a Department of Audiology and Speech Pathology, University of Tennessee at Knoxville, 578 South Stadium Hall, Knoxville, TN 37996-0740, United States
b University of Illinois at Urbana-Champaign, United States Received 30 January 2008; received in revised form 13 November 2008; accepted 5 January 2009
Abstract A significant number of bilinguals in English-speaking countries speak Korean as their first language. One such country is the
United States (U.S.). As the U.S. becomes increasingly diverse, providing more effective services for culturally and linguistically diverse children is a critical issue and growing challenge for speech-language pathologists. The U.S. Census Bureau reports that the number of Korean immigrants in the U.S. has steadily increased over the past decade. As a result, a greater number of children who speak Korean as a first or second language may need speech, language, and hearing services. This paper provides a review of the literature on (1) phonological characteristics of the Korean language and (2) speech sound acquisition and developmental patterns for phonological processes in Korean children. We illustrate how language knowledge of Korean might impact the learning of English based on case studies of three Korean children speaking English in the U.S. We describe considerations for more appropriate evaluation and treatment of speech sound disorders in Korean-English-speaking children.
Learning outcomes: Readers will be able to: (1) understand phonological characteristics of the Korean language and speech sound acquisition and developmental patterns for phonological process in Korean children, (2) describe characteristics of English speech sound acquisition in successive bilingual English-Korean learners and interference patterns that result from the influence of two independent phonological and phonetic systems, and (3) describe considerations and clinical implications for the more appropriate evaluation and treatment of speech sound disorders in Korean-English speaking children. Published by Elsevier Inc.
1. Introduction
Due to the cultural and linguistic diversity of many English-speaking countries, providing more effective services for culturally and linguistically diverse children is a big challenge for speech-language pathologists. The present paper focuses on one such country, the United States (U.S.), and one language other than English spoken by a substantial number of its people: Korean. The U.S. Census Bureau results show that foreign born individuals from Korea made up the seventh-largest immigrant group in 2000 (U.S. Bureau of the Census, 2006). Within the Asian population in the United States, the number of foreign born people from Korea increased by 52% between 1990 and 2000. The Overseas Koreans Foundation (http://eng.korean.net) reported that the Korean immigrant population in the U.S. in 2007 was
* Corresponding author. E-mail address: [email protected] (S. Ha).
0021-9924/$ – see front matter. Published by Elsevier Inc. doi:10.1016/j.jcomdis.2009.01.002
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approximately 2 million. It is projected that more than half of the Korean immigrants speak Korean at home (U.S. Bureau of the Census, 2006).
Given the substantial increases in the Korean immigrant population in the U.S., we might expect the number of bilingual children speaking Korean and English to have increased. Consequently, speech-language pathologists will more likely encounter bilingual children speaking Korean and English who show phonological disorders. The issue of clinical service for bilingual children speaking Korean and English is also important in other English-speaking countries including Canada, Australia, the United Kingdom (U.K.), and New Zealand. According to the Overseas Koreans Foundation, there were approximately 2.5 million Korean immigrants living in English-speaking countries in 2007.
Yavas and Goldstein (1998) suggested that speech-language pathologists should understand ‘‘common and uncommon phonological patterns in first and second language acquisition and bilingual phonology, interference patterns between languages, dialect patterns, and language-specific patterns that are exhibited in one language but not in the other’’ (p. 58). To identify these patterns, speech-language pathologists need basic knowledge about Korean phonology as it compares to English. It is necessary to identify and discern the causes of the children’s phonological problems, which might include difficulty with English phonological acquisition due to the effect of a second language, the nature of Korean or English phonology, or underlying phonological problems without regard to either of the two languages. This knowledge makes it possible to provide appropriate clinical services to Korean children with phonological disorders.
The characteristics of bilingual speech acquisition are different with respect to types of bilingualism (i.e., simultaneous bilingual speaker versus successive bilingual speaker) and levels of language dominance (Yavas, 2007). If children move to countries speaking English after they have nearly or completely acquired their native Korean language, their Korean phonological and phonetic system might have a strong influence on English speech production. In such cases, it is critical to differentiate Korean children who are phonologically disordered in one or both languages from Korean children who demonstrate typical phonological development in their native language and whose errors in English merely reflect the influence of the Korean language. Knowledge about phonological characteristics of the Korean language contrasted with English is needed to provide accurate speech evaluation and appropriate speech treatment.
The purpose of the present paper is to provide a literature review on phonological characteristics of the Korean language in comparison to English, as spoken by adults, and speech sound acquisition and developmental patterns for phonological processes in Korean children. Also, we provide case studies of three Korean children speaking English in the U.S. The three children are successive bilingual learners as they were born in Korea and have completely acquired the Korean speech sound system before moving to the U.S. We expect that these case studies will show characteristics of English speech sound acquisition typical of successive bilingual learners and interference patterns that result from the influence of two independent phonological and phonetic systems (Paradis, 2001). We illustrate how language knowledge of Korean might impact the learning of English, and we describe considerations and clinical implications for the more appropriate evaluation and treatment of speech sound disorders in Korean-English-speaking children, based on a literature review and case studies.
2. The Korean language
The Korean language is composed of seven geographically based dialects including the Central dialect, which has been considered the standard Korean dialect in South Korea, and the Phyengan dialect, designated as the standard Korean dialect in North Korea (Sohn, 1999). Although there are geographical and socio-political dialectal differences, the Korean language is relatively homogeneous, whereby speakers from different areas can communicate with each other with little effort or difficulty. In particular, due to mass media and education based on standard Korean, dialects in South Korea have become standardized (centralized) and more homogeneous. Approximately 75 million people in the world speak Korean as a first language (Kim & Pae, 2007). The Korean Culture and Information Service (http:// www. Korea.net) reported that there are 48 million people in South Korea, 22 million in North Korea, and 5 million outside of Korea who speak Korean as their first language.
2.1. The sound patterns of the Korean language
The sound patterns of standard Korean consist of 19 consonants, 10 vowels, 2 semivowels, and 11 diphthongs (Lee & Ramsey, 2000; Sohn, 1999).
Table 1 Korean vowels. Place
Tongue High Mid Low
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Front
Lips
Unround
i e e
Round
y ø
Central Lips Unround <
Back Lips Unround
K a
165
Round u o
2.1.1. Vowels and diphthongs The 10 vowels of Korean can be categorized with respect to tongue position (high–mid–low, front–central–back)
and lip rounding (rounding–unrounding) in the same manner as English (see Table 1). In standard production, all Korean vowels are voiced and nonnasal like English vowels. Both Korean and English vowels are nasalized for a certain duration when they precede or follow nasal consonants (Ha & Kuehn, 2006). Unlike English vowel production that is described as tense (long) or lax (short) (Kent, 2004), Korean vowels are not categorized in terms of tense or lax features. Several studies of English vowel production and perception in Korean speakers suggest that Korean speakers learning English or Korean-English bilinguals have difficulty perceiving and producing English vowels in the same manner as native English speakers (e.g., Bohn & Flege, 1992; Ingram & Park, 1997; Tsukada et al., 2005). The major findings of these studies were that Korean speakers show difficulty with perception and production of English /i/-/I/ and /e/-/æ/ contrasts due to differences between the vowel systems of English and Korean, especially the lack of a ‘‘tense–lax’’ distinction in the Korean vowel system.
One distinctive characteristic of the Korean vowel system is its diphthongs. Two semivowels, /w/ and /j/, are described as combining with other vowels to form 11 diphthongs: /ja, je, jo, ju, jaj, jej, wa, we, waj, wej, uj/. It remains to be demonstrated acoustically or physiologically, however, whether these ‘‘diphthongs’’ truly are different from glide plus vowel or vowel plus glide combinations in the English system. Assuming that such difference exists, it may take more time for Korean children to master diphthongs than single vowels with regard to pronunciation and spelling, due to the relatively greater number of sounds classified as phonemic diphthongs in Korean than English and the possible difficulty of articulating diphthongs. Indeed, Korean literature about the developmental pattern of Korean vowels indicates that all the vowels are acquired before age 3 but some diphthongs, in particular /wa, we, waj, wej/, are not acquired even by the age of 5 (Kwon, 1981; Um, 1994).
2.1.2. Consonants Table 2 provides a classification of the 19 Korean consonants by manner and place of articulation and includes the
English consonant system for better understanding of contrastive and noncontrastive characteristics of the consonant systems of the two languages. Korean has fewer consonants than English. Korean has neither labiodental fricatives nor linguadental fricatives such as the /f/, /v/, /u/, and /ð/ of English. Also, the /z/, /R/, /a/, /V/, /./, and /r/ sounds do not exist in Korean.
In Korean, all consonants except nasal /E/ can occur in the initial position of a word, but only seven consonants, /p/, / t/, /k/, /m/, /n/, /E/, and /l/ can occur in syllable-final position. In syllable-final position, only variants of stops that traditionally have been described as lax consonants (e.g., /p, t, k/) are allowed; and in that position, the consonants are unreleased. When the lips close to articulate the final /p/ of /cip/ meaning ‘‘house’’, for example, they remain closed, with no breath of air escaping. This feature of production is different from the optional release of English consonants in syllable-final position.
Originally, /l/ did not normally occur in word-initial position in Korean. There are no native Korean words that begin with this consonant. Modern borrowings, however, do not follow this pattern, and there are many loan words in Korean today beginning with /l/ (e.g., line pronounced as /la-in/). The phonetic characteristics of /l/ sounds in syllableinitial and final positions are different from each other. In word-final position the consonant /l/ is always produced as a lateral approximant, whereas /l/ in word-initial position is frequently produced as a flap consonant, which is produced with a brief contraction of the muscles so that the tongue is thrust against the alveolar ridge (Lee, 1989). The consonant /n/ is another phoneme that does not normally occur in word-initial position when followed by the vowels /i/ or /y/, but modern loans from English are not subject to this constraint (Lee & Ramsey, 2000).
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Table 2 Korean and English consonants.
Bilabial
Labiodental
Linguadental
Linguaalveolar
Linguapalatal
Velar
Glottal
K
E
K
E
K
E
K
E
K
E
K
E
K
E
Stop (Plosive)
Tense
/p*/
Laxa
/p/
Aspirate
/ph/
Voiceless
/p/
Voiced
/b/
/t*/ /t/ /th/
/t/ /d/
/k*/ /k/ /kh/
/k/ /g/
Affricate Tense Lax Aspirate Voiceless Voiced
/c*/
/c/ /ch/
/V/ /./
Fricative Tense Lax Aspirate Voiceless Voiced
/s*/ /s/
/f/
/u/
/s/
/R/
/v/
/ð/
/z/
/a/
/h/ /h/
Nasal Liquid Glide
/m/
/m/
/w/
/n/
/n/
/l/
/l/
/E/
/E/
/r/
/j/
Note: K = Korean; E = English; * = traditionally described as having a ‘‘tense’’ quality in Korean; h = traditionally described as having an
‘‘aspirated’’ quality in Korean. a Korean symbols /p, t, k, c, s/ without the diacritics * and h are traditionally described as have a ‘‘lax’’ quality.
It is a convention in Korean linguistics to characterize Korean stops and the fricatives /s/ and /s*/with a languagespecific set of features (see Table 2). Whereas English stop consonants are conventionally categorized by features of voicing and aspiration (i.e., Lisker & Abramson, 1964), Korean linguistic convention is to classify Korean stop consonants by degree of tensity (tensing) and aspiration (e.g., Kim, 1965). Korean linguists do not consider there to be any voicing contrast in Korean. They consider all stop and fricative consonants to be voiceless, except for the lax stops which may become lightly voiced between voiced sounds. Regardless of whether or not one agrees with the characterization of all Korean stops and fricatives as voiceless, phonemically in Korean there is a three-way contrast (tense–lax–aspirate) in stop consonants and palatal affricates, a two-way contrast (tense–lax) in the alveolar fricatives, and no contrast for the glottal fricative /h/ (Sohn, 1999). The consonants /p*/, /t*/, /c*/, /k*/, and /s*/ are categorized as tense (or ‘‘fortis’’ or ‘‘reinforced’’), where the symbol [*] is used in keeping with the conventions of the published literature on Korean phonology. The consonants /p/, /t/, /c/, /k/, and /s/ are categorized as lax (or ‘‘plain’’); and the consonants /ph/, /th/, /ch/, /kh/, and /h/, as aspirate. The remaining four consonants are liquid and nasal consonants, /l/, / m/, /n/, and /E/.
The classification of consonants by the articulatory features, tense, lax, and aspirate reflects a characteristic of the Korean language which is not found in most other languages. Kim (1965) was the first to provide evidence that it is not the voicing feature but a tensity feature that is the primary feature for discriminating among Korean stop consonants, based on acoustic, airflow, palatographic, and electromyographic data. The tense feature (tensity) continues into the vowel, giving it a throaty or laryngeal quality according to perceptual classifications by native Korean phoneticians (Lee & Ramsey, 2000). In a review of the literature by Yoon (2007), it was found that several studies have provided additional evidence to support the notion of tensity as a perceptual feature: for acoustic features such as voice onset time (VOT) (Hardcastle, 1973) and fundamental frequency (Choi, 2002), perceptual features such as pitch (Kim & Duanmu, 2004), and physical production features such as duration of linguapalatal contact (Cho & Keating, 2001) and intraoral pressure (Cho, Jun, & Ladefoged, 2002). Whether or not these features result in a perceptual interpretation of
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a ‘‘voiced’’ or ‘‘voiceless’’ quality similar to English can only be determined by comparing such perceptual interpretations of Korean and English stops and fricatives by both English and Korean native speakers.
Kim (1965) also suggested that VOT is a secondary feature for differentiating Korean stop consonants. The consonants classified as tense are pronounced with the shortest VOT among the stop consonants, about a 12 ms VOT, indicating little aspiration. The consonants classified as lax or ‘‘plain’’ are slightly aspirated in word-initial position and produced with a longer voicing delay of about 30–50 ms. The terms ‘‘tense’’ and ‘‘lax,’’ as used in the Korean system, may be confusing in relation to the use of these terms in the English system, given that consonants with short VOT in English are sometimes classified as lax and those with longer VOT are sometimes classified as tense, or ‘‘fortis,’’ i.e., the reverse of the descriptions in Korean. However, consonants classified as ‘‘aspirated’’ in the Korean system are produced with strong aspiration lasting approximately 100 ms (Lee & Ramsey, 2000). English voiceless consonants are generally produced with about 70–85 ms of voicing delay and aspiration, about mid-way between the VOT values of Korean lax and aspirated consonants; as a result, English speakers are often unable to hear the distinction between the Korean lax and aspirated consonants (Lee & Ramsey, 2000).
McCrea and Morris (2005) described English voiced stops as usually displaying VOT durations of 0–25 ms (see also Forrest, Weismer, & Turner, 1989; Lisker & Abramson, 1964) although the VOT values of English voiced consonants have shown variation in terms of speakers and may show a negative range as great as À170 to À210 (Caramazza, Yeni-Komshian, Zurif, & Carbone, 1973; Zlatin, 1974). English speakers tend to identify the Korean tense consonants with the voiced consonants of their own language, which might be due to the fact that English voiced stops (i.e., /b, d, g/) show a positive VOT range that overlaps that of Korean ‘‘tense’’ stops (e.g., /p*, t*, k*/). However, the tense consonants are considered voiceless as well as unaspirated because voice onset of the Korean tense consonants occurs almost simultaneously with release of the burst of the consonant (Lee & Ramsey, 2000). The distribution of VOTs for the ‘‘tense’’ stops of Korean appears to never be as negative as the voiced stops of English, perhaps contributing to the claim that all Korean stops are ‘‘voiceless.’’
There is a two-way distinction for the alveolar fricatives: /s*/ and /s/, that is, tense and lax (Sohn, 1999). Unlike all the other lax consonants, /s/ does not become voiced between vowels. It is always pronounced as a voiceless fricative. There is no phonemic /z/ in Korean, as described earlier. Korean consonant /s/ has only slight air escape, which sounds unlike the /s/ of English. The Korean tense consonant /s*/ often sounds more like the /s/ of English than does the Korean /s/ (Lee & Ramsey, 2000). When speaking English, Koreans often pronounce English /s/ with the tense quality of the /s*/ in their own language. Furthermore, the lax, or plain /s/ is palatalized before /i/ and the diphthong, /wi/, that is, Korean /si/ sounds like /Ri/ and /swi/ like /Rwi/ (e.g., swiri, meaning ‘‘name of fish,’’ pronounced as /Rwi-ri/). Tense / s*/ is usually not palatalized. Kim (1996) reported that the /s*/ phoneme is the last consonant that typically developing Korean children acquire. It is assumed that young children have difficulty pronouncing /s*/ accurately due to the combination of the fricative manner and the tense feature.
In addition, the most distinctive contrast between Korean and English is associated with consonant clusters. The Korean phonetic syllable structure is of the form (C)(G)V(C) which consists of only one optional consonant (C) and one optional glide or semivowel (G) in the initial position, and one optional consonant in word-final position. A vowel (V) is the only obligatory element in the Korean phonetic syllable structure (Sohn, 1999). Due to the influence of this phonetic syllable structure, Korean speakers tend to insert a vowel [<] when they pronounce words including consonant clusters. For instance, the single-syllable English word ‘‘strike’’ is borrowed as a four-syllable word [s<-th<-lai-kh<] (Sohn, 1999). Similarly, Korean written words with consonant clusters lose one consonant when spoken, because two consonants are not acceptable in postvocalic position in spoken Korean (e.g., kaps, meaning ‘‘price’’ ! /kap/). This characteristic of Korean phonetic syllable structure shows that there are no syllable-initial or syllable-final consonant clusters in spoken Korean, in contrast to English. Therefore, with respect to phonological development, Korean children do not have speech problems related to syllable-initial or syllable-final consonant clusters as identified in English-speaking children. Rather, Korean children speaking English are likely to show vowel addition between syllable-initial or syllable-final consonant clusters. Also, Korean children have some difficulty spelling and reading consonant clusters in Korean print, due to a difference between the written and spoken systems of Korean (i.e., changes in pronunciation governed by phonological rules) for consonant clusters. For example, young Korean children are easily confused by the spelling of the Korean word, talk (pronounced as /tak/ and meaning ‘‘chicken’’).
Compared to English, which is a ‘‘stress-timed’’ language, Korean is a ‘‘syllable-timed’’ language. Each syllable in the Korean language is distinctly pronounced, with equal stress. Instead of having consonant clusters in its phonetic syllable structure, Korean has syllabic consonant clusters which occur between two syllables, in word-medial position.
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For example, in the Korean word, yangmal (pronounced as /jaE-mal/, meaning ‘‘socks’’), each syllable of the word is equally stressed and distinctly pronounced. Both /E/ and /m/ are located in word-medial position, with /E/ located in syllable-final position and /m/ in syllable-initial position. Thus, the two sounds form a syllabic consonant cluster in the
word-medial position.
As another example of differences in syllabification, the two-syllable English word ‘‘lipstick’’ is borrowed as a
three-syllable word [lip-s<-tik]. The consonants /p/ in syllable-final position and /t/ in syllable-initial position are located in word-medial position, which is acceptable in the Korean language. However, consonant clusters like /st/ do
not exist in spoken Korean and therefore the vowel / simplification (i.e., deletion of one consonant of a syllabic cluster) in Korean children. For example, young Korean
children are likely to pronounce yangmal /jaE-mal/ as /ja-mal/.
3. Speech sound acquisition
The Korean literature on speech sound acquisition shows language-specific developmental patterns of Koreanspeaking children as well as universal developmental patterns similar to those reported in the literature for English. With regard to similarities, in children who speak English and those who speak Korean as a first language, early inventories contain stops, nasals, and glides, whereas fricatives and liquids are among the last acquired sounds. Anterior sounds (i.e., labial and alveolar) tend to precede posterior ones and, therefore, bilabial and alveolar sounds are earlier acquired than palatal and velar sounds (e.g., Dodd, Holm, Hua, & Sharon, 2003; Goldman & Fristoe, 2000; Kim & Pae, 2005). At age 2 years, word-final phonetic repertoires are much smaller than word-initial repertoires (Kim, 1996; Stoel-Gammon, 1985). A comparison of the basic and common patterns of acquisition in children speaking either Korean or English as a first language would support the existence of certain universal patterns and a fairly predictable order of acquisition.
The timing of the acquisition of each Korean sound is slightly different among studies due to variations in the test target words, criteria for age of acquisition, methods of analysis, and so on. Kim and Pae (2005) have reported the most recent normative data on children’s development of Korean phonology (see Table 3). Using naturalistic samples of speech, they investigated production accuracy of Korean consonants, developmental order, and age of acquisition of phonemes in 220 Korean children between the ages of 2;6 and 6;5 living in Seoul, South Korea. The authors reported the Percentage of Consonants Correct (PCC) as well as the Percentage of Consonants Correct-Revised (PCC-R), in 6month intervals. Common and uncommon clinical consonant distortions were scored as correct for PCC-R (Shriberg,
Table 3 Developmental patterns of Korean consonants (Kim & Pae, 2005).
Age
Developmental stage of phonemes
2;6–2;11 3;0–3;5
Customary
/k*/, /kh/, /th/, SI/t/, /c*/ /ch/, SI& SF /n/ SI & SF /m/, SF /l/ SF /p/, SF /t/, SI /k/ SF /k/, SF/E/
/c/, SI /l/
Acquisition /ph/, /h/, SI /p/
/k*/, /c*/, /ch/, /th/ SI /n/, SI /t/, SF /m/, SF /p/, SI /k/
Mastery /p*/, /t*/
/k*/, /th/, /ph/, /h/, SI /p/, SF /t/, SI /m/, SI /n/, SF /l/
3;6–3;11
/s/
4;0–4;5
4;6–4;11
/s*/
5:0–5;5
5;6–5;11
6;0–6;5
/c/, SF/n/ /kh/, SF /k/, SF/E/
SI /l/
SF /p/ /c/, /c*/, /ch/, SI /t/ SI /k/, SF /m/, SF/n/ /kh/, SF /k/, SF/E/
SI /l/
Note: Customary = age of customary correct production (i.e., 50–74% of children in an age group produce the sound correctly); acquisition = age of acquisition (i.e., 75–89% of children in an age group produce the sound correctly); mastery = age of mastery (i.e., 90–100% of children in an age group produce the sound correctly). SI = syllable-initial position; SF = syllable-final position. These ages were determined using the PCC (rather than PCC-R) metric.
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Austin, Lewis, McSweeny, & Wilson, 1997a). In addition, the authors demonstrated that the 19 Korean consonants may show different ages of acquisition in various syllable and word positions. Because Korean is a syllable-timed language, the authors separately considered each phoneme in syllable-initial position, both word-initially and wordmedially, and in syllable-final position, both word-medially and word-finally.
The authors found that 2-year-old Korean children earn scores of approximately 60% for PCC and 70% for PCC-R, averaged across 43 Korean consonants, including the various positions. PCC increased most remarkably between 2;6 and 3;11, and children over 4 years of age earned PCC and PCC-R scores of more than 90%. Using a specified criterion for age of acquisition (i.e., 75–89% of children in an age group produced the sound correctly), Kim and Pae reported that by late 2 or 3 years, Korean children have acquired stops and nasals (except for velars in syllable-final position), the glottal fricative /h/, liquids in syllable-final position, and affricates. Korean children acquire velars in syllable-final position by age 4 and liquids in syllable-initial position by age 5. The last acquired sounds are the alveolar fricatives, / s/ and /s*/, which are not yet acquired even when children are 6;5. When common and uncommon clinical consonant distortions are scored as correct, Korean children acquire /l/ in syllable-initial position by age 4 and /s/ and /s*/ by age 5 (i.e., 1 year earlier than when such distortions are scored as errors).
All phonemes except /l/ generally emerge and are acquired earlier in syllable-initial position than in syllable-final position. In contrast, /l/ first emerges in syllable-final position and then emerges in syllable-initial. This result regarding the acquisition of /l/ is consistent with that of Um (1994) with respect to Korean consonants, as well as that of Stoel-Gammon and Dunn (1985) with respect to English consonants. Kim and Pae (2005) suggest that this different pattern of acquisition of /l/ from that of other consonants might be due to different phonetic characteristics of Korean / l/ sounds in syllable-initial position (often a flap) and final position (always a lateral approximant). Giles and Moll (1975) also found articulatory differences between pre- and postvocalic /l/ in English speakers which appear to be consistent with the findings for Korean speakers. With regard to consonant manner, typically developing Korean children appear to acquire tense, aspirate, and lax stops and affricates in that order, with the three-way stop contrast acquired by age 4 (Kim & Pae, 2005; Kim & Stoel-Gammon, 2007). Unlike the tense-before-lax acquisition order for stops and affricates, however, the Korean lax fricative /s/ appears to be acquired earlier than the tense fricative /s*/.
The Korean literature consistently reports that /s/ and /s*/ are the last acquired sounds in typical speech development. Furthermore, the acquisition periods for /s/ and /s*/ are protracted compared to other phonemes (Kim & Pae, 2005). Even children aged 6;5 in the Kim and Pae (2005) study had not yet reached the age of acquisition for correct production of /s/ and /s*/ (i.e., correct production by 75–89% of children, as seen in Table 2). In addition, /s/ and /s*/ are the most frequently replaced (i.e., error) sounds in the speech of children with articulation and phonological disorders (Chun & Lee, 1999). Um (1994) showed that typically developing Korean children aged 3–4 years often replaced /s/ with /t/, /h/, and /c/ or produced a lingua-dentalized /s/ which sounds like the English phoneme /u/.
Chun and Lee (1999) reported developmental patterns (i.e., rate and period of acquisition and percent of production accuracy) for /s/ and /s*/ in typically developing Korean children between the ages of 2 and 7 years, with some differences due to the vowel context. The results of the study suggest that the developmental error pattern for /s/ progresses in the following order: from deletion; to substitution by /h/, /th/, and then palatalized /s/; to correct production of /s/. Likewise, the developmental error pattern for /s*/ progresses in the following order: from deletion, to substitution by /h/, /t*/, palatalized /s*/, and then /s/. Based on an acquisition criterion of 75% correct for /s/ in various vowel contexts, /s/ in the /si/, /s3/, and /s
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articulation from these same consonants before other vowels. Young Korean children are able to produce palatalized / s/ and /s*/ with relative ease and at earlier ages. Chun and Lee (1999) concluded that the /i/ vowel context elicits accurate production of /s/ and /s*/ relatively easily. This has clinical implications for the diagnosis and treatment of children with articulation and phonological disorders in Korean, namely that /s/ and /s*/ preceding the vowel /i/ would be a good starting point for children who have difficulty in producing /s/ and /s*/.
With regard to developmental phonological patterns for Korean and English, the most striking contrasts are associated with consonant clusters and some phonemes that do not exist in Korean such as /u/ and /ð/. Englishspeaking children show a longer period for acquiring all the speech sounds of the language than those speaking Korean, perhaps due to consonant clusters and the phonemes /u/ and /ð/ (i.e., Shriberg, 1993; Shriberg et al., 1997a; Shriberg, Austin, Lewis, McSweeny, & Wilson, 1997b; Smit, Hand, Freilinger, Bernthal, & Bird, 1990). Koreanspeaking children are usually expected to acquire all the sounds in Korean and show adult-like articulation and phonological ability around 6 or 7 years of age. In contrast, the acquisition process for consonants and consonant clusters in English-speaking children continues until 9 years of age according to some accounts (e.g., Smit, 1993; Smit et al., 1990). The last acquired consonants in Korean are /s/ and /s*/, which are acquired by 6 or 7 years, whereas among the last acquired singleton consonants in English are /u/ and /ð/, which are typically acquired at 7 or 8 years (Chun & Lee, 1999; Kim, 1992a, 1996; Smit et al., 1990), and /s/ and /z/, which according to some normative studies may not be mastered by 90% of children until 9 years (Smit et al., 1990). Shriberg and his colleagues report ‘‘Late-8’’ consonants from a profile of consonant mastery taken from a group of 64 children aged 3–6 years with speech delays (Shriberg, 1993; Shriberg et al., 1997a,b). The Late-8 consonants included /u/, /ð/, /s/, /z/, /R/, /a/, /l/, and /r/, and these consonants averaged less than 25% correct in continuous conversational speech. Because of their late acquisition, both in children with and without speech delays (see also Goldstein, Fabiano, & Washington, 2005), the Late-8 consonants could be considered as ‘‘marked’’ in the language or greater in complexity.
The preceding English developmental sound patterns suggest that Korean children speaking English might have even more difficulty in acquiring and correctly articulating consonant clusters and some sounds that do not exist in Korean. Among the Late-8 consonants of English, all sounds except for /s/ and /l/ do not exist in Korean. Therefore, this characteristic suggests that speech-language pathologists working with Korean children speaking English should pay special attention to the six marked consonants, /u/, /ð/, /z/, /R/, /a/, and /r/. Furthermore, for the development of Korean, it would be helpful to consider the Korean ‘‘Late 7’’ consonants /s/, /s*/, /l/, /k/, /kh/, /c/, /c*/, which we have identified on the basis of the Korean literature as marked or more complex, due to their late acquisition (Kim & Pae, 2005; Kim & Stoel-Gammon, 2007; Um, 1994).
4. Phonological processes
Some Korean studies have reported phonological error patterns which occur frequently in the speech of Korean children between 2 and 6 years of age (Han & Shin, 1987; Kim, 1995, 1992a,b, 2006; Kim & Shin, 1992; Pae, 1987). Kim (2006) investigated phonological error patterns in 220 Korean preschool children aged 2;6 to 6;5 using a preliminary version of Assessment of Phonology and Articulation for Children (APAC) (Kim, Pae, & Park, 2007). She found that more than 10% of late 2-year-olds showed the following phonological processes more than three times: (1) reduplication or consonant harmony, (2) word-final consonant deletion, (3) syllabic cluster simplification, (4) tensing, (5) deaspiration, (6) velar fronting, (7) nasalization or stopping of liquids, (8) liquid simplification, (9) affrication, (10) palatalization, (11) stopping of fricatives or affricates, and (12) interdentalization of fricatives. Among these phonological processes, (1) reduplication or consonant harmony, (2) word-final consonant deletion, (3) nasalization or stopping of liquids, (4) velar fronting, (5) tensing, and (6) deaspiration resolved by age 3. By age 4, (1) syllabic cluster simplification, (2) liquid simplification, (3) affrication and (4) palatalization had resolved, and by age 5, stopping of fricatives or affricates had disappeared.
Kim (1995) also investigated phonological processes in 60 children with articulation disorders and 60 children with normal speech. Kim showed that there was no phonological pattern that occurred more than 10% of the time in typically developing 4-year-old Korean children. Also, the author reported that children with articulation disorders showed significant differences compared to children with normal speech in terms of higher frequency of developmental phonological patterns and more deviant processes (i.e., greater than 40% occurrence for such patterns or processes in possible contexts). The term ‘‘deviant processes’’ refers to phonological patterns which do not usually occur in the speech of typically developing children. Deviant processes found in the speech of children with
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articulation disorders included: (1) deletion of bilabial and alveolar plosives, (2) deaspiration (changing a feature of aspirate consonants), and (3) fronting of the glottal fricative, /h/. Kim (1995) suggested that these deviant phonological processes should be considered a higher priority for treatment than those commonly used by typically developing children.
In the Korean literature, the age when some phonological processes disappear is consistent with that reported in the literature for English. Stoel-Gammon and Dunn (1985) and Smit (1993) reported that final consonant deletion usually disappears by about age 3 and some phonological processes such as cluster reduction usually persist after age 3. Likewise, word-final consonant deletion in the speech of Korean children resolves at age 3 and syllabic (word-medial) cluster simplification usually persists after age 3 (Kim, 2006).
According to the literature on developmental phonology in the two languages, both Korean-speaking and Englishspeaking children show common simplification patterns, such as sound (or syllable) deletion or reduction, and assimilation patterns, such as fronting near other front consonants. The literature consistently suggests that common phonological patterns in both languages are resolved around 3–4 years of age in the speech of typically developing children.
Besides common phonological patterns, some specific phonological patterns can be identified in each language that would not be applicable to the other language. For example, consonant cluster reduction, prevocalic voicing, and devoicing of word-final consonants, processes that frequently occur in English-speaking children, are not applicable to Korean-speaking children because unlike English, Korean has no consonant clusters in word-initial or word-final position, and Korean consonants are not distinguished by the feature of voicing (i.e., are not considered to have both voiced and voiceless sounds). Instead, Korean-speaking children frequently show syllabic cluster simplification in the word-medial position, and tensing or deaspiration of prevocalic or word-final consonants related to the three-way contrast of stops and affricates in Korean (i.e., tense–lax–aspirate contrasts).
5. Contrastive analysis
When successive bilingual children produce English, it is valuable for speech-language pathologists to be able to discern whether phonological patterns that fail to match adult English reflect the influence of the Korean language (i.e., interference patterns) or a phonological disorder. One approach commonly used is contrastive analysis (Owens, 2008, pp. 403–406; Leonard & Weiss, 1983; McGregor, Williams, Hearst, & Johnson, 1997). In the contrastive framework for viewing bilingual acquisition, sounds found in the second language or L2 (e.g., /r/ in English) that are absent in the first language or L1 (e.g., Korean) are considered difficult for the individual to produce, and may result in error patterns for those L2 targets. McGregor et al. (1997) state that ‘‘contrastive analysis is a method for separating expressive speech-language patterns that are consistent with a client’s first dialect or language (D1/L1) from patterns that represent true errors’’ (p. 45). True errors, which cannot be accounted for by L1 influences or typical developmental patterns for L2, would be considered signs of a phonological disorder. In the present paper, our intent is to identify L1 patterns of Korean that may influence L2 English acquisition.
Contrastive analysis is not the only framework in which bilingual development can be examined. Interlanguage phenomena that do not reflect either L1 or L2, but rather general constraints on language learning, have attracted interest in recent years. Such phenomena in bilingual children could be indicated by bidirectional cross-linguistic effects, as described by Vihman and McLaughlin (1982) and reported by Keshavarz and Ingram (2002) for a Farsi-English bilingual child. These effects may arise from differences in the phonemic repertoires of the two languages, positional constraints, or phonotactic constraints (Goldstein et al., 2005). Interlanguage phenomena are perhaps best examined by comparison of bilinguals to monolinguals in each language, which is beyond the scope of the present paper (for recent examples, see Goldstein et al., 2005). Regardless, Goldstein and colleagues report that cross-linguistic effects are infrequent in the speech of children, accounting for less than 1% of all consonants produced in their studies of Spanish-English bilinguals, and perhaps more likely to be demonstrated by children younger than 5 years of age. Similarly, in the study by Goldstein et al. (2005), it was rare for bilingual children to produce substitutions atypical in monolingual development, making it difficult to distinguish interlanguage phenomena from common substitutions used by monolingual children (Vihman & McLaughlin, 1982). Consequently, the present paper employs only contrastive analysis of the phonemic repertoires of Korean and English to make predictions about how bilingual children might produce English.
When the phonemic repertoire of Korean is contrasted with that of English (see Tables 1 and 2), there are at least 7 vowel and 12 consonant phonemes in English that do not exist in Korean. According to contrastive analysis, our
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prediction is that these English sounds should be susceptible to change by successive bilingual speakers. The sounds include (a) the vowels and diphthongs, /I, æ, U, &, aI, &I, aU/, and (b) the consonants, /b, d, g, f, v, u, ð, z, R, a, da, r/. Because /u, ð, z, R, a, r/ are among the Late-8 consonants acquired in English, they may be doubly challenging for Korean successive bilingual children to learn.
With respect to phonological processes, Korean children speaking English may show not only processes that frequently occur in the speech of children who are native speakers of English, but also specific processes influenced by the Korean language (for a similar argument, see McGregor et al., 1997). The number of occurrences for each phonological process in Korean children speaking English would therefore be expected to be different from that reported for children developing English as their native language. The contrastive framework suggests a number of predictions for phonological simplification of English by successive bilinguals due to the influence of the Korean language. First, because Korean lacks a number of English vowels, we predict that successive bilingual children will exhibit vowel deviations in English. Among these vowel-related deviations, we also predict the occurrence of vowelization of /2/, because rhotic quality does not exist in Korean. Second, because Korean has a reduced repertoire of final consonants compared to English, we predict the occurrence of word-final consonant omission beyond the typical age range for monolingual English-speaking children, i.e., beyond the age of 2;6 (Owens, 2008, p. 406; Preisser, Hodson, & Paden, 1988). Third, because the three-way lax–tense–aspirate contrast for obstruents in Korean does not directly correspond to the two-way voiced–voiceless contrast in English, we predict voicing alterations in English. Specifically, if the lax Korean stops, /p, t, k/, are substituted for the voiceless English stops, /p, t, k/, English transcribers are likely to perceive voiced English cognates, /b, d, g/. Fourth, given that English fricatives and affricates for the most part are not shared with the Korean sound system, we predict that stopping, sibilant distortions, and deaffrication in Korean children speaking English might be more prevalent than in monolingual English-speaking children. Because the lax /s/ in Korean is acquired earlier than the tense /s*/, lax /s/ most likely would be the substitute chosen by children for the English /s/. Recall, though, that the Korean lax /s/ is made with much weaker frication than the English /s/. This might result in sibilant distortions in English. Additionally, because the Korean /s/ is palatalized when it co-occurs with /I/, we predict that palatalization of English /s/ may occur. Other patterns affecting manner or place of fricatives or affricates also might be predicted, such as affrication and depalatalization. Lastly, it is likely that Korean children speaking English may have even more difficulty in acquiring consonant clusters in word-initial and word-final positions than young monolingual speakers of English and may more frequently show cluster reduction. Bilingual children may show vowel addition between adjacent consonants in English (i.e., epenthesis) as well. With these predictions in mind, we turn to several case studies to examine actual occurrences of sound errors in successive bilingual children.
6. Case studies
The following are case studies of three Korean children speaking English. All three children were born in Korea and lived in an exclusively monolingual Korean-speaking environment before moving with their families to Knoxville, TN, in the U.S. All three speak the standard Korean (Central) dialect, and in the U.S., have received exposure primarily to the Appalachian regional dialect of American English, as spoken in Knoxville (Flipsen, 2007; Owens, 2008, p. 395). The three children have no history of speech and language problems related to the Korean language, hearing problems, or orofacial anomalies based on parental report. The three children have learned and speak English in their community and their regular education programs, but speak only Korean at home. All three children can be considered successive, rather than simultaneous, bilingual Korean (L1)–English (L2) speakers, because they were first exposed to English (L2) after the age of 3;0 (Owens, 2008) and had largely completed acquisition of Korean phonology at the time of data of collection. In addition, the contexts in which they speak and are exposed to Korean and English are clearly separate.
The children differ, however, with regard to the following factors which are critical to speech sound acquisition in bilingual speakers: chronological age, age of beginning exposure to English, and amount of time being exposed to and producing English. The three children have been included here to provide insight into the interaction between dual phonological and phonetic systems. Presumably these successive bilingual speakers have two separate phonological systems, yet interference patterns may be still be evident (Paradis, 2001). Also, this set of cases can be considered as a pilot study to examine the relation between speech acquisition patterns in bilingual speakers and general demographic factors that describe their bilingual experience (i.e., age, amount of exposure and experience with each language, etc.).
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Tutorial Paper
Characteristics of Korean phonology: Review, tutorial, and case studies of Korean children speaking English
Seunghee Ha a,*, Cynthia J. Johnson b, David P. Kuehn b
a Department of Audiology and Speech Pathology, University of Tennessee at Knoxville, 578 South Stadium Hall, Knoxville, TN 37996-0740, United States
b University of Illinois at Urbana-Champaign, United States Received 30 January 2008; received in revised form 13 November 2008; accepted 5 January 2009
Abstract A significant number of bilinguals in English-speaking countries speak Korean as their first language. One such country is the
United States (U.S.). As the U.S. becomes increasingly diverse, providing more effective services for culturally and linguistically diverse children is a critical issue and growing challenge for speech-language pathologists. The U.S. Census Bureau reports that the number of Korean immigrants in the U.S. has steadily increased over the past decade. As a result, a greater number of children who speak Korean as a first or second language may need speech, language, and hearing services. This paper provides a review of the literature on (1) phonological characteristics of the Korean language and (2) speech sound acquisition and developmental patterns for phonological processes in Korean children. We illustrate how language knowledge of Korean might impact the learning of English based on case studies of three Korean children speaking English in the U.S. We describe considerations for more appropriate evaluation and treatment of speech sound disorders in Korean-English-speaking children.
Learning outcomes: Readers will be able to: (1) understand phonological characteristics of the Korean language and speech sound acquisition and developmental patterns for phonological process in Korean children, (2) describe characteristics of English speech sound acquisition in successive bilingual English-Korean learners and interference patterns that result from the influence of two independent phonological and phonetic systems, and (3) describe considerations and clinical implications for the more appropriate evaluation and treatment of speech sound disorders in Korean-English speaking children. Published by Elsevier Inc.
1. Introduction
Due to the cultural and linguistic diversity of many English-speaking countries, providing more effective services for culturally and linguistically diverse children is a big challenge for speech-language pathologists. The present paper focuses on one such country, the United States (U.S.), and one language other than English spoken by a substantial number of its people: Korean. The U.S. Census Bureau results show that foreign born individuals from Korea made up the seventh-largest immigrant group in 2000 (U.S. Bureau of the Census, 2006). Within the Asian population in the United States, the number of foreign born people from Korea increased by 52% between 1990 and 2000. The Overseas Koreans Foundation (http://eng.korean.net) reported that the Korean immigrant population in the U.S. in 2007 was
* Corresponding author. E-mail address: [email protected] (S. Ha).
0021-9924/$ – see front matter. Published by Elsevier Inc. doi:10.1016/j.jcomdis.2009.01.002
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approximately 2 million. It is projected that more than half of the Korean immigrants speak Korean at home (U.S. Bureau of the Census, 2006).
Given the substantial increases in the Korean immigrant population in the U.S., we might expect the number of bilingual children speaking Korean and English to have increased. Consequently, speech-language pathologists will more likely encounter bilingual children speaking Korean and English who show phonological disorders. The issue of clinical service for bilingual children speaking Korean and English is also important in other English-speaking countries including Canada, Australia, the United Kingdom (U.K.), and New Zealand. According to the Overseas Koreans Foundation, there were approximately 2.5 million Korean immigrants living in English-speaking countries in 2007.
Yavas and Goldstein (1998) suggested that speech-language pathologists should understand ‘‘common and uncommon phonological patterns in first and second language acquisition and bilingual phonology, interference patterns between languages, dialect patterns, and language-specific patterns that are exhibited in one language but not in the other’’ (p. 58). To identify these patterns, speech-language pathologists need basic knowledge about Korean phonology as it compares to English. It is necessary to identify and discern the causes of the children’s phonological problems, which might include difficulty with English phonological acquisition due to the effect of a second language, the nature of Korean or English phonology, or underlying phonological problems without regard to either of the two languages. This knowledge makes it possible to provide appropriate clinical services to Korean children with phonological disorders.
The characteristics of bilingual speech acquisition are different with respect to types of bilingualism (i.e., simultaneous bilingual speaker versus successive bilingual speaker) and levels of language dominance (Yavas, 2007). If children move to countries speaking English after they have nearly or completely acquired their native Korean language, their Korean phonological and phonetic system might have a strong influence on English speech production. In such cases, it is critical to differentiate Korean children who are phonologically disordered in one or both languages from Korean children who demonstrate typical phonological development in their native language and whose errors in English merely reflect the influence of the Korean language. Knowledge about phonological characteristics of the Korean language contrasted with English is needed to provide accurate speech evaluation and appropriate speech treatment.
The purpose of the present paper is to provide a literature review on phonological characteristics of the Korean language in comparison to English, as spoken by adults, and speech sound acquisition and developmental patterns for phonological processes in Korean children. Also, we provide case studies of three Korean children speaking English in the U.S. The three children are successive bilingual learners as they were born in Korea and have completely acquired the Korean speech sound system before moving to the U.S. We expect that these case studies will show characteristics of English speech sound acquisition typical of successive bilingual learners and interference patterns that result from the influence of two independent phonological and phonetic systems (Paradis, 2001). We illustrate how language knowledge of Korean might impact the learning of English, and we describe considerations and clinical implications for the more appropriate evaluation and treatment of speech sound disorders in Korean-English-speaking children, based on a literature review and case studies.
2. The Korean language
The Korean language is composed of seven geographically based dialects including the Central dialect, which has been considered the standard Korean dialect in South Korea, and the Phyengan dialect, designated as the standard Korean dialect in North Korea (Sohn, 1999). Although there are geographical and socio-political dialectal differences, the Korean language is relatively homogeneous, whereby speakers from different areas can communicate with each other with little effort or difficulty. In particular, due to mass media and education based on standard Korean, dialects in South Korea have become standardized (centralized) and more homogeneous. Approximately 75 million people in the world speak Korean as a first language (Kim & Pae, 2007). The Korean Culture and Information Service (http:// www. Korea.net) reported that there are 48 million people in South Korea, 22 million in North Korea, and 5 million outside of Korea who speak Korean as their first language.
2.1. The sound patterns of the Korean language
The sound patterns of standard Korean consist of 19 consonants, 10 vowels, 2 semivowels, and 11 diphthongs (Lee & Ramsey, 2000; Sohn, 1999).
Table 1 Korean vowels. Place
Tongue High Mid Low
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Front
Lips
Unround
i e e
Round
y ø
Central Lips Unround <
Back Lips Unround
K a
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Round u o
2.1.1. Vowels and diphthongs The 10 vowels of Korean can be categorized with respect to tongue position (high–mid–low, front–central–back)
and lip rounding (rounding–unrounding) in the same manner as English (see Table 1). In standard production, all Korean vowels are voiced and nonnasal like English vowels. Both Korean and English vowels are nasalized for a certain duration when they precede or follow nasal consonants (Ha & Kuehn, 2006). Unlike English vowel production that is described as tense (long) or lax (short) (Kent, 2004), Korean vowels are not categorized in terms of tense or lax features. Several studies of English vowel production and perception in Korean speakers suggest that Korean speakers learning English or Korean-English bilinguals have difficulty perceiving and producing English vowels in the same manner as native English speakers (e.g., Bohn & Flege, 1992; Ingram & Park, 1997; Tsukada et al., 2005). The major findings of these studies were that Korean speakers show difficulty with perception and production of English /i/-/I/ and /e/-/æ/ contrasts due to differences between the vowel systems of English and Korean, especially the lack of a ‘‘tense–lax’’ distinction in the Korean vowel system.
One distinctive characteristic of the Korean vowel system is its diphthongs. Two semivowels, /w/ and /j/, are described as combining with other vowels to form 11 diphthongs: /ja, je, jo, ju, jaj, jej, wa, we, waj, wej, uj/. It remains to be demonstrated acoustically or physiologically, however, whether these ‘‘diphthongs’’ truly are different from glide plus vowel or vowel plus glide combinations in the English system. Assuming that such difference exists, it may take more time for Korean children to master diphthongs than single vowels with regard to pronunciation and spelling, due to the relatively greater number of sounds classified as phonemic diphthongs in Korean than English and the possible difficulty of articulating diphthongs. Indeed, Korean literature about the developmental pattern of Korean vowels indicates that all the vowels are acquired before age 3 but some diphthongs, in particular /wa, we, waj, wej/, are not acquired even by the age of 5 (Kwon, 1981; Um, 1994).
2.1.2. Consonants Table 2 provides a classification of the 19 Korean consonants by manner and place of articulation and includes the
English consonant system for better understanding of contrastive and noncontrastive characteristics of the consonant systems of the two languages. Korean has fewer consonants than English. Korean has neither labiodental fricatives nor linguadental fricatives such as the /f/, /v/, /u/, and /ð/ of English. Also, the /z/, /R/, /a/, /V/, /./, and /r/ sounds do not exist in Korean.
In Korean, all consonants except nasal /E/ can occur in the initial position of a word, but only seven consonants, /p/, / t/, /k/, /m/, /n/, /E/, and /l/ can occur in syllable-final position. In syllable-final position, only variants of stops that traditionally have been described as lax consonants (e.g., /p, t, k/) are allowed; and in that position, the consonants are unreleased. When the lips close to articulate the final /p/ of /cip/ meaning ‘‘house’’, for example, they remain closed, with no breath of air escaping. This feature of production is different from the optional release of English consonants in syllable-final position.
Originally, /l/ did not normally occur in word-initial position in Korean. There are no native Korean words that begin with this consonant. Modern borrowings, however, do not follow this pattern, and there are many loan words in Korean today beginning with /l/ (e.g., line pronounced as /la-in/). The phonetic characteristics of /l/ sounds in syllableinitial and final positions are different from each other. In word-final position the consonant /l/ is always produced as a lateral approximant, whereas /l/ in word-initial position is frequently produced as a flap consonant, which is produced with a brief contraction of the muscles so that the tongue is thrust against the alveolar ridge (Lee, 1989). The consonant /n/ is another phoneme that does not normally occur in word-initial position when followed by the vowels /i/ or /y/, but modern loans from English are not subject to this constraint (Lee & Ramsey, 2000).
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Table 2 Korean and English consonants.
Bilabial
Labiodental
Linguadental
Linguaalveolar
Linguapalatal
Velar
Glottal
K
E
K
E
K
E
K
E
K
E
K
E
K
E
Stop (Plosive)
Tense
/p*/
Laxa
/p/
Aspirate
/ph/
Voiceless
/p/
Voiced
/b/
/t*/ /t/ /th/
/t/ /d/
/k*/ /k/ /kh/
/k/ /g/
Affricate Tense Lax Aspirate Voiceless Voiced
/c*/
/c/ /ch/
/V/ /./
Fricative Tense Lax Aspirate Voiceless Voiced
/s*/ /s/
/f/
/u/
/s/
/R/
/v/
/ð/
/z/
/a/
/h/ /h/
Nasal Liquid Glide
/m/
/m/
/w/
/n/
/n/
/l/
/l/
/E/
/E/
/r/
/j/
Note: K = Korean; E = English; * = traditionally described as having a ‘‘tense’’ quality in Korean; h = traditionally described as having an
‘‘aspirated’’ quality in Korean. a Korean symbols /p, t, k, c, s/ without the diacritics * and h are traditionally described as have a ‘‘lax’’ quality.
It is a convention in Korean linguistics to characterize Korean stops and the fricatives /s/ and /s*/with a languagespecific set of features (see Table 2). Whereas English stop consonants are conventionally categorized by features of voicing and aspiration (i.e., Lisker & Abramson, 1964), Korean linguistic convention is to classify Korean stop consonants by degree of tensity (tensing) and aspiration (e.g., Kim, 1965). Korean linguists do not consider there to be any voicing contrast in Korean. They consider all stop and fricative consonants to be voiceless, except for the lax stops which may become lightly voiced between voiced sounds. Regardless of whether or not one agrees with the characterization of all Korean stops and fricatives as voiceless, phonemically in Korean there is a three-way contrast (tense–lax–aspirate) in stop consonants and palatal affricates, a two-way contrast (tense–lax) in the alveolar fricatives, and no contrast for the glottal fricative /h/ (Sohn, 1999). The consonants /p*/, /t*/, /c*/, /k*/, and /s*/ are categorized as tense (or ‘‘fortis’’ or ‘‘reinforced’’), where the symbol [*] is used in keeping with the conventions of the published literature on Korean phonology. The consonants /p/, /t/, /c/, /k/, and /s/ are categorized as lax (or ‘‘plain’’); and the consonants /ph/, /th/, /ch/, /kh/, and /h/, as aspirate. The remaining four consonants are liquid and nasal consonants, /l/, / m/, /n/, and /E/.
The classification of consonants by the articulatory features, tense, lax, and aspirate reflects a characteristic of the Korean language which is not found in most other languages. Kim (1965) was the first to provide evidence that it is not the voicing feature but a tensity feature that is the primary feature for discriminating among Korean stop consonants, based on acoustic, airflow, palatographic, and electromyographic data. The tense feature (tensity) continues into the vowel, giving it a throaty or laryngeal quality according to perceptual classifications by native Korean phoneticians (Lee & Ramsey, 2000). In a review of the literature by Yoon (2007), it was found that several studies have provided additional evidence to support the notion of tensity as a perceptual feature: for acoustic features such as voice onset time (VOT) (Hardcastle, 1973) and fundamental frequency (Choi, 2002), perceptual features such as pitch (Kim & Duanmu, 2004), and physical production features such as duration of linguapalatal contact (Cho & Keating, 2001) and intraoral pressure (Cho, Jun, & Ladefoged, 2002). Whether or not these features result in a perceptual interpretation of
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a ‘‘voiced’’ or ‘‘voiceless’’ quality similar to English can only be determined by comparing such perceptual interpretations of Korean and English stops and fricatives by both English and Korean native speakers.
Kim (1965) also suggested that VOT is a secondary feature for differentiating Korean stop consonants. The consonants classified as tense are pronounced with the shortest VOT among the stop consonants, about a 12 ms VOT, indicating little aspiration. The consonants classified as lax or ‘‘plain’’ are slightly aspirated in word-initial position and produced with a longer voicing delay of about 30–50 ms. The terms ‘‘tense’’ and ‘‘lax,’’ as used in the Korean system, may be confusing in relation to the use of these terms in the English system, given that consonants with short VOT in English are sometimes classified as lax and those with longer VOT are sometimes classified as tense, or ‘‘fortis,’’ i.e., the reverse of the descriptions in Korean. However, consonants classified as ‘‘aspirated’’ in the Korean system are produced with strong aspiration lasting approximately 100 ms (Lee & Ramsey, 2000). English voiceless consonants are generally produced with about 70–85 ms of voicing delay and aspiration, about mid-way between the VOT values of Korean lax and aspirated consonants; as a result, English speakers are often unable to hear the distinction between the Korean lax and aspirated consonants (Lee & Ramsey, 2000).
McCrea and Morris (2005) described English voiced stops as usually displaying VOT durations of 0–25 ms (see also Forrest, Weismer, & Turner, 1989; Lisker & Abramson, 1964) although the VOT values of English voiced consonants have shown variation in terms of speakers and may show a negative range as great as À170 to À210 (Caramazza, Yeni-Komshian, Zurif, & Carbone, 1973; Zlatin, 1974). English speakers tend to identify the Korean tense consonants with the voiced consonants of their own language, which might be due to the fact that English voiced stops (i.e., /b, d, g/) show a positive VOT range that overlaps that of Korean ‘‘tense’’ stops (e.g., /p*, t*, k*/). However, the tense consonants are considered voiceless as well as unaspirated because voice onset of the Korean tense consonants occurs almost simultaneously with release of the burst of the consonant (Lee & Ramsey, 2000). The distribution of VOTs for the ‘‘tense’’ stops of Korean appears to never be as negative as the voiced stops of English, perhaps contributing to the claim that all Korean stops are ‘‘voiceless.’’
There is a two-way distinction for the alveolar fricatives: /s*/ and /s/, that is, tense and lax (Sohn, 1999). Unlike all the other lax consonants, /s/ does not become voiced between vowels. It is always pronounced as a voiceless fricative. There is no phonemic /z/ in Korean, as described earlier. Korean consonant /s/ has only slight air escape, which sounds unlike the /s/ of English. The Korean tense consonant /s*/ often sounds more like the /s/ of English than does the Korean /s/ (Lee & Ramsey, 2000). When speaking English, Koreans often pronounce English /s/ with the tense quality of the /s*/ in their own language. Furthermore, the lax, or plain /s/ is palatalized before /i/ and the diphthong, /wi/, that is, Korean /si/ sounds like /Ri/ and /swi/ like /Rwi/ (e.g., swiri, meaning ‘‘name of fish,’’ pronounced as /Rwi-ri/). Tense / s*/ is usually not palatalized. Kim (1996) reported that the /s*/ phoneme is the last consonant that typically developing Korean children acquire. It is assumed that young children have difficulty pronouncing /s*/ accurately due to the combination of the fricative manner and the tense feature.
In addition, the most distinctive contrast between Korean and English is associated with consonant clusters. The Korean phonetic syllable structure is of the form (C)(G)V(C) which consists of only one optional consonant (C) and one optional glide or semivowel (G) in the initial position, and one optional consonant in word-final position. A vowel (V) is the only obligatory element in the Korean phonetic syllable structure (Sohn, 1999). Due to the influence of this phonetic syllable structure, Korean speakers tend to insert a vowel [<] when they pronounce words including consonant clusters. For instance, the single-syllable English word ‘‘strike’’ is borrowed as a four-syllable word [s<-th<-lai-kh<] (Sohn, 1999). Similarly, Korean written words with consonant clusters lose one consonant when spoken, because two consonants are not acceptable in postvocalic position in spoken Korean (e.g., kaps, meaning ‘‘price’’ ! /kap/). This characteristic of Korean phonetic syllable structure shows that there are no syllable-initial or syllable-final consonant clusters in spoken Korean, in contrast to English. Therefore, with respect to phonological development, Korean children do not have speech problems related to syllable-initial or syllable-final consonant clusters as identified in English-speaking children. Rather, Korean children speaking English are likely to show vowel addition between syllable-initial or syllable-final consonant clusters. Also, Korean children have some difficulty spelling and reading consonant clusters in Korean print, due to a difference between the written and spoken systems of Korean (i.e., changes in pronunciation governed by phonological rules) for consonant clusters. For example, young Korean children are easily confused by the spelling of the Korean word, talk (pronounced as /tak/ and meaning ‘‘chicken’’).
Compared to English, which is a ‘‘stress-timed’’ language, Korean is a ‘‘syllable-timed’’ language. Each syllable in the Korean language is distinctly pronounced, with equal stress. Instead of having consonant clusters in its phonetic syllable structure, Korean has syllabic consonant clusters which occur between two syllables, in word-medial position.
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For example, in the Korean word, yangmal (pronounced as /jaE-mal/, meaning ‘‘socks’’), each syllable of the word is equally stressed and distinctly pronounced. Both /E/ and /m/ are located in word-medial position, with /E/ located in syllable-final position and /m/ in syllable-initial position. Thus, the two sounds form a syllabic consonant cluster in the
word-medial position.
As another example of differences in syllabification, the two-syllable English word ‘‘lipstick’’ is borrowed as a
three-syllable word [lip-s<-tik]. The consonants /p/ in syllable-final position and /t/ in syllable-initial position are located in word-medial position, which is acceptable in the Korean language. However, consonant clusters like /st/ do
not exist in spoken Korean and therefore the vowel / simplification (i.e., deletion of one consonant of a syllabic cluster) in Korean children. For example, young Korean
children are likely to pronounce yangmal /jaE-mal/ as /ja-mal/.
3. Speech sound acquisition
The Korean literature on speech sound acquisition shows language-specific developmental patterns of Koreanspeaking children as well as universal developmental patterns similar to those reported in the literature for English. With regard to similarities, in children who speak English and those who speak Korean as a first language, early inventories contain stops, nasals, and glides, whereas fricatives and liquids are among the last acquired sounds. Anterior sounds (i.e., labial and alveolar) tend to precede posterior ones and, therefore, bilabial and alveolar sounds are earlier acquired than palatal and velar sounds (e.g., Dodd, Holm, Hua, & Sharon, 2003; Goldman & Fristoe, 2000; Kim & Pae, 2005). At age 2 years, word-final phonetic repertoires are much smaller than word-initial repertoires (Kim, 1996; Stoel-Gammon, 1985). A comparison of the basic and common patterns of acquisition in children speaking either Korean or English as a first language would support the existence of certain universal patterns and a fairly predictable order of acquisition.
The timing of the acquisition of each Korean sound is slightly different among studies due to variations in the test target words, criteria for age of acquisition, methods of analysis, and so on. Kim and Pae (2005) have reported the most recent normative data on children’s development of Korean phonology (see Table 3). Using naturalistic samples of speech, they investigated production accuracy of Korean consonants, developmental order, and age of acquisition of phonemes in 220 Korean children between the ages of 2;6 and 6;5 living in Seoul, South Korea. The authors reported the Percentage of Consonants Correct (PCC) as well as the Percentage of Consonants Correct-Revised (PCC-R), in 6month intervals. Common and uncommon clinical consonant distortions were scored as correct for PCC-R (Shriberg,
Table 3 Developmental patterns of Korean consonants (Kim & Pae, 2005).
Age
Developmental stage of phonemes
2;6–2;11 3;0–3;5
Customary
/k*/, /kh/, /th/, SI/t/, /c*/ /ch/, SI& SF /n/ SI & SF /m/, SF /l/ SF /p/, SF /t/, SI /k/ SF /k/, SF/E/
/c/, SI /l/
Acquisition /ph/, /h/, SI /p/
/k*/, /c*/, /ch/, /th/ SI /n/, SI /t/, SF /m/, SF /p/, SI /k/
Mastery /p*/, /t*/
/k*/, /th/, /ph/, /h/, SI /p/, SF /t/, SI /m/, SI /n/, SF /l/
3;6–3;11
/s/
4;0–4;5
4;6–4;11
/s*/
5:0–5;5
5;6–5;11
6;0–6;5
/c/, SF/n/ /kh/, SF /k/, SF/E/
SI /l/
SF /p/ /c/, /c*/, /ch/, SI /t/ SI /k/, SF /m/, SF/n/ /kh/, SF /k/, SF/E/
SI /l/
Note: Customary = age of customary correct production (i.e., 50–74% of children in an age group produce the sound correctly); acquisition = age of acquisition (i.e., 75–89% of children in an age group produce the sound correctly); mastery = age of mastery (i.e., 90–100% of children in an age group produce the sound correctly). SI = syllable-initial position; SF = syllable-final position. These ages were determined using the PCC (rather than PCC-R) metric.
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Austin, Lewis, McSweeny, & Wilson, 1997a). In addition, the authors demonstrated that the 19 Korean consonants may show different ages of acquisition in various syllable and word positions. Because Korean is a syllable-timed language, the authors separately considered each phoneme in syllable-initial position, both word-initially and wordmedially, and in syllable-final position, both word-medially and word-finally.
The authors found that 2-year-old Korean children earn scores of approximately 60% for PCC and 70% for PCC-R, averaged across 43 Korean consonants, including the various positions. PCC increased most remarkably between 2;6 and 3;11, and children over 4 years of age earned PCC and PCC-R scores of more than 90%. Using a specified criterion for age of acquisition (i.e., 75–89% of children in an age group produced the sound correctly), Kim and Pae reported that by late 2 or 3 years, Korean children have acquired stops and nasals (except for velars in syllable-final position), the glottal fricative /h/, liquids in syllable-final position, and affricates. Korean children acquire velars in syllable-final position by age 4 and liquids in syllable-initial position by age 5. The last acquired sounds are the alveolar fricatives, / s/ and /s*/, which are not yet acquired even when children are 6;5. When common and uncommon clinical consonant distortions are scored as correct, Korean children acquire /l/ in syllable-initial position by age 4 and /s/ and /s*/ by age 5 (i.e., 1 year earlier than when such distortions are scored as errors).
All phonemes except /l/ generally emerge and are acquired earlier in syllable-initial position than in syllable-final position. In contrast, /l/ first emerges in syllable-final position and then emerges in syllable-initial. This result regarding the acquisition of /l/ is consistent with that of Um (1994) with respect to Korean consonants, as well as that of Stoel-Gammon and Dunn (1985) with respect to English consonants. Kim and Pae (2005) suggest that this different pattern of acquisition of /l/ from that of other consonants might be due to different phonetic characteristics of Korean / l/ sounds in syllable-initial position (often a flap) and final position (always a lateral approximant). Giles and Moll (1975) also found articulatory differences between pre- and postvocalic /l/ in English speakers which appear to be consistent with the findings for Korean speakers. With regard to consonant manner, typically developing Korean children appear to acquire tense, aspirate, and lax stops and affricates in that order, with the three-way stop contrast acquired by age 4 (Kim & Pae, 2005; Kim & Stoel-Gammon, 2007). Unlike the tense-before-lax acquisition order for stops and affricates, however, the Korean lax fricative /s/ appears to be acquired earlier than the tense fricative /s*/.
The Korean literature consistently reports that /s/ and /s*/ are the last acquired sounds in typical speech development. Furthermore, the acquisition periods for /s/ and /s*/ are protracted compared to other phonemes (Kim & Pae, 2005). Even children aged 6;5 in the Kim and Pae (2005) study had not yet reached the age of acquisition for correct production of /s/ and /s*/ (i.e., correct production by 75–89% of children, as seen in Table 2). In addition, /s/ and /s*/ are the most frequently replaced (i.e., error) sounds in the speech of children with articulation and phonological disorders (Chun & Lee, 1999). Um (1994) showed that typically developing Korean children aged 3–4 years often replaced /s/ with /t/, /h/, and /c/ or produced a lingua-dentalized /s/ which sounds like the English phoneme /u/.
Chun and Lee (1999) reported developmental patterns (i.e., rate and period of acquisition and percent of production accuracy) for /s/ and /s*/ in typically developing Korean children between the ages of 2 and 7 years, with some differences due to the vowel context. The results of the study suggest that the developmental error pattern for /s/ progresses in the following order: from deletion; to substitution by /h/, /th/, and then palatalized /s/; to correct production of /s/. Likewise, the developmental error pattern for /s*/ progresses in the following order: from deletion, to substitution by /h/, /t*/, palatalized /s*/, and then /s/. Based on an acquisition criterion of 75% correct for /s/ in various vowel contexts, /s/ in the /si/, /s3/, and /s
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articulation from these same consonants before other vowels. Young Korean children are able to produce palatalized / s/ and /s*/ with relative ease and at earlier ages. Chun and Lee (1999) concluded that the /i/ vowel context elicits accurate production of /s/ and /s*/ relatively easily. This has clinical implications for the diagnosis and treatment of children with articulation and phonological disorders in Korean, namely that /s/ and /s*/ preceding the vowel /i/ would be a good starting point for children who have difficulty in producing /s/ and /s*/.
With regard to developmental phonological patterns for Korean and English, the most striking contrasts are associated with consonant clusters and some phonemes that do not exist in Korean such as /u/ and /ð/. Englishspeaking children show a longer period for acquiring all the speech sounds of the language than those speaking Korean, perhaps due to consonant clusters and the phonemes /u/ and /ð/ (i.e., Shriberg, 1993; Shriberg et al., 1997a; Shriberg, Austin, Lewis, McSweeny, & Wilson, 1997b; Smit, Hand, Freilinger, Bernthal, & Bird, 1990). Koreanspeaking children are usually expected to acquire all the sounds in Korean and show adult-like articulation and phonological ability around 6 or 7 years of age. In contrast, the acquisition process for consonants and consonant clusters in English-speaking children continues until 9 years of age according to some accounts (e.g., Smit, 1993; Smit et al., 1990). The last acquired consonants in Korean are /s/ and /s*/, which are acquired by 6 or 7 years, whereas among the last acquired singleton consonants in English are /u/ and /ð/, which are typically acquired at 7 or 8 years (Chun & Lee, 1999; Kim, 1992a, 1996; Smit et al., 1990), and /s/ and /z/, which according to some normative studies may not be mastered by 90% of children until 9 years (Smit et al., 1990). Shriberg and his colleagues report ‘‘Late-8’’ consonants from a profile of consonant mastery taken from a group of 64 children aged 3–6 years with speech delays (Shriberg, 1993; Shriberg et al., 1997a,b). The Late-8 consonants included /u/, /ð/, /s/, /z/, /R/, /a/, /l/, and /r/, and these consonants averaged less than 25% correct in continuous conversational speech. Because of their late acquisition, both in children with and without speech delays (see also Goldstein, Fabiano, & Washington, 2005), the Late-8 consonants could be considered as ‘‘marked’’ in the language or greater in complexity.
The preceding English developmental sound patterns suggest that Korean children speaking English might have even more difficulty in acquiring and correctly articulating consonant clusters and some sounds that do not exist in Korean. Among the Late-8 consonants of English, all sounds except for /s/ and /l/ do not exist in Korean. Therefore, this characteristic suggests that speech-language pathologists working with Korean children speaking English should pay special attention to the six marked consonants, /u/, /ð/, /z/, /R/, /a/, and /r/. Furthermore, for the development of Korean, it would be helpful to consider the Korean ‘‘Late 7’’ consonants /s/, /s*/, /l/, /k/, /kh/, /c/, /c*/, which we have identified on the basis of the Korean literature as marked or more complex, due to their late acquisition (Kim & Pae, 2005; Kim & Stoel-Gammon, 2007; Um, 1994).
4. Phonological processes
Some Korean studies have reported phonological error patterns which occur frequently in the speech of Korean children between 2 and 6 years of age (Han & Shin, 1987; Kim, 1995, 1992a,b, 2006; Kim & Shin, 1992; Pae, 1987). Kim (2006) investigated phonological error patterns in 220 Korean preschool children aged 2;6 to 6;5 using a preliminary version of Assessment of Phonology and Articulation for Children (APAC) (Kim, Pae, & Park, 2007). She found that more than 10% of late 2-year-olds showed the following phonological processes more than three times: (1) reduplication or consonant harmony, (2) word-final consonant deletion, (3) syllabic cluster simplification, (4) tensing, (5) deaspiration, (6) velar fronting, (7) nasalization or stopping of liquids, (8) liquid simplification, (9) affrication, (10) palatalization, (11) stopping of fricatives or affricates, and (12) interdentalization of fricatives. Among these phonological processes, (1) reduplication or consonant harmony, (2) word-final consonant deletion, (3) nasalization or stopping of liquids, (4) velar fronting, (5) tensing, and (6) deaspiration resolved by age 3. By age 4, (1) syllabic cluster simplification, (2) liquid simplification, (3) affrication and (4) palatalization had resolved, and by age 5, stopping of fricatives or affricates had disappeared.
Kim (1995) also investigated phonological processes in 60 children with articulation disorders and 60 children with normal speech. Kim showed that there was no phonological pattern that occurred more than 10% of the time in typically developing 4-year-old Korean children. Also, the author reported that children with articulation disorders showed significant differences compared to children with normal speech in terms of higher frequency of developmental phonological patterns and more deviant processes (i.e., greater than 40% occurrence for such patterns or processes in possible contexts). The term ‘‘deviant processes’’ refers to phonological patterns which do not usually occur in the speech of typically developing children. Deviant processes found in the speech of children with
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articulation disorders included: (1) deletion of bilabial and alveolar plosives, (2) deaspiration (changing a feature of aspirate consonants), and (3) fronting of the glottal fricative, /h/. Kim (1995) suggested that these deviant phonological processes should be considered a higher priority for treatment than those commonly used by typically developing children.
In the Korean literature, the age when some phonological processes disappear is consistent with that reported in the literature for English. Stoel-Gammon and Dunn (1985) and Smit (1993) reported that final consonant deletion usually disappears by about age 3 and some phonological processes such as cluster reduction usually persist after age 3. Likewise, word-final consonant deletion in the speech of Korean children resolves at age 3 and syllabic (word-medial) cluster simplification usually persists after age 3 (Kim, 2006).
According to the literature on developmental phonology in the two languages, both Korean-speaking and Englishspeaking children show common simplification patterns, such as sound (or syllable) deletion or reduction, and assimilation patterns, such as fronting near other front consonants. The literature consistently suggests that common phonological patterns in both languages are resolved around 3–4 years of age in the speech of typically developing children.
Besides common phonological patterns, some specific phonological patterns can be identified in each language that would not be applicable to the other language. For example, consonant cluster reduction, prevocalic voicing, and devoicing of word-final consonants, processes that frequently occur in English-speaking children, are not applicable to Korean-speaking children because unlike English, Korean has no consonant clusters in word-initial or word-final position, and Korean consonants are not distinguished by the feature of voicing (i.e., are not considered to have both voiced and voiceless sounds). Instead, Korean-speaking children frequently show syllabic cluster simplification in the word-medial position, and tensing or deaspiration of prevocalic or word-final consonants related to the three-way contrast of stops and affricates in Korean (i.e., tense–lax–aspirate contrasts).
5. Contrastive analysis
When successive bilingual children produce English, it is valuable for speech-language pathologists to be able to discern whether phonological patterns that fail to match adult English reflect the influence of the Korean language (i.e., interference patterns) or a phonological disorder. One approach commonly used is contrastive analysis (Owens, 2008, pp. 403–406; Leonard & Weiss, 1983; McGregor, Williams, Hearst, & Johnson, 1997). In the contrastive framework for viewing bilingual acquisition, sounds found in the second language or L2 (e.g., /r/ in English) that are absent in the first language or L1 (e.g., Korean) are considered difficult for the individual to produce, and may result in error patterns for those L2 targets. McGregor et al. (1997) state that ‘‘contrastive analysis is a method for separating expressive speech-language patterns that are consistent with a client’s first dialect or language (D1/L1) from patterns that represent true errors’’ (p. 45). True errors, which cannot be accounted for by L1 influences or typical developmental patterns for L2, would be considered signs of a phonological disorder. In the present paper, our intent is to identify L1 patterns of Korean that may influence L2 English acquisition.
Contrastive analysis is not the only framework in which bilingual development can be examined. Interlanguage phenomena that do not reflect either L1 or L2, but rather general constraints on language learning, have attracted interest in recent years. Such phenomena in bilingual children could be indicated by bidirectional cross-linguistic effects, as described by Vihman and McLaughlin (1982) and reported by Keshavarz and Ingram (2002) for a Farsi-English bilingual child. These effects may arise from differences in the phonemic repertoires of the two languages, positional constraints, or phonotactic constraints (Goldstein et al., 2005). Interlanguage phenomena are perhaps best examined by comparison of bilinguals to monolinguals in each language, which is beyond the scope of the present paper (for recent examples, see Goldstein et al., 2005). Regardless, Goldstein and colleagues report that cross-linguistic effects are infrequent in the speech of children, accounting for less than 1% of all consonants produced in their studies of Spanish-English bilinguals, and perhaps more likely to be demonstrated by children younger than 5 years of age. Similarly, in the study by Goldstein et al. (2005), it was rare for bilingual children to produce substitutions atypical in monolingual development, making it difficult to distinguish interlanguage phenomena from common substitutions used by monolingual children (Vihman & McLaughlin, 1982). Consequently, the present paper employs only contrastive analysis of the phonemic repertoires of Korean and English to make predictions about how bilingual children might produce English.
When the phonemic repertoire of Korean is contrasted with that of English (see Tables 1 and 2), there are at least 7 vowel and 12 consonant phonemes in English that do not exist in Korean. According to contrastive analysis, our
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prediction is that these English sounds should be susceptible to change by successive bilingual speakers. The sounds include (a) the vowels and diphthongs, /I, æ, U, &, aI, &I, aU/, and (b) the consonants, /b, d, g, f, v, u, ð, z, R, a, da, r/. Because /u, ð, z, R, a, r/ are among the Late-8 consonants acquired in English, they may be doubly challenging for Korean successive bilingual children to learn.
With respect to phonological processes, Korean children speaking English may show not only processes that frequently occur in the speech of children who are native speakers of English, but also specific processes influenced by the Korean language (for a similar argument, see McGregor et al., 1997). The number of occurrences for each phonological process in Korean children speaking English would therefore be expected to be different from that reported for children developing English as their native language. The contrastive framework suggests a number of predictions for phonological simplification of English by successive bilinguals due to the influence of the Korean language. First, because Korean lacks a number of English vowels, we predict that successive bilingual children will exhibit vowel deviations in English. Among these vowel-related deviations, we also predict the occurrence of vowelization of /2/, because rhotic quality does not exist in Korean. Second, because Korean has a reduced repertoire of final consonants compared to English, we predict the occurrence of word-final consonant omission beyond the typical age range for monolingual English-speaking children, i.e., beyond the age of 2;6 (Owens, 2008, p. 406; Preisser, Hodson, & Paden, 1988). Third, because the three-way lax–tense–aspirate contrast for obstruents in Korean does not directly correspond to the two-way voiced–voiceless contrast in English, we predict voicing alterations in English. Specifically, if the lax Korean stops, /p, t, k/, are substituted for the voiceless English stops, /p, t, k/, English transcribers are likely to perceive voiced English cognates, /b, d, g/. Fourth, given that English fricatives and affricates for the most part are not shared with the Korean sound system, we predict that stopping, sibilant distortions, and deaffrication in Korean children speaking English might be more prevalent than in monolingual English-speaking children. Because the lax /s/ in Korean is acquired earlier than the tense /s*/, lax /s/ most likely would be the substitute chosen by children for the English /s/. Recall, though, that the Korean lax /s/ is made with much weaker frication than the English /s/. This might result in sibilant distortions in English. Additionally, because the Korean /s/ is palatalized when it co-occurs with /I/, we predict that palatalization of English /s/ may occur. Other patterns affecting manner or place of fricatives or affricates also might be predicted, such as affrication and depalatalization. Lastly, it is likely that Korean children speaking English may have even more difficulty in acquiring consonant clusters in word-initial and word-final positions than young monolingual speakers of English and may more frequently show cluster reduction. Bilingual children may show vowel addition between adjacent consonants in English (i.e., epenthesis) as well. With these predictions in mind, we turn to several case studies to examine actual occurrences of sound errors in successive bilingual children.
6. Case studies
The following are case studies of three Korean children speaking English. All three children were born in Korea and lived in an exclusively monolingual Korean-speaking environment before moving with their families to Knoxville, TN, in the U.S. All three speak the standard Korean (Central) dialect, and in the U.S., have received exposure primarily to the Appalachian regional dialect of American English, as spoken in Knoxville (Flipsen, 2007; Owens, 2008, p. 395). The three children have no history of speech and language problems related to the Korean language, hearing problems, or orofacial anomalies based on parental report. The three children have learned and speak English in their community and their regular education programs, but speak only Korean at home. All three children can be considered successive, rather than simultaneous, bilingual Korean (L1)–English (L2) speakers, because they were first exposed to English (L2) after the age of 3;0 (Owens, 2008) and had largely completed acquisition of Korean phonology at the time of data of collection. In addition, the contexts in which they speak and are exposed to Korean and English are clearly separate.
The children differ, however, with regard to the following factors which are critical to speech sound acquisition in bilingual speakers: chronological age, age of beginning exposure to English, and amount of time being exposed to and producing English. The three children have been included here to provide insight into the interaction between dual phonological and phonetic systems. Presumably these successive bilingual speakers have two separate phonological systems, yet interference patterns may be still be evident (Paradis, 2001). Also, this set of cases can be considered as a pilot study to examine the relation between speech acquisition patterns in bilingual speakers and general demographic factors that describe their bilingual experience (i.e., age, amount of exposure and experience with each language, etc.).
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