Production Accuracy of English and Korean Consonant and Vowel Categories in 3-year-old Simultaneous Korean-English Bilingual Children in the U.S.

Objectives: In the United States, phonological development in bilingual children has been exclusively investigated in Indo-European languages such as Spanish-English bilinguals, while very limited research has been conducted in children who learn both Korean and English simultaneously. The purpose of this study was to examine whether Korean-English bilingual (KEB) children produced consonants and vowels similar to their monolingual English (ME) and monolingual Korean (MK) peers. In addition, English and Korean consonants and vowels were compared within KEB and between monolingual and bilingual children to examine whether production accuracy can be explained by the size and complexity of sound categories. Methods: Single word productions were collected from 24 children (8 KEB, 8 MK, 8ME) using a picture naming task. All bilingual children who were exposed to both languages before 18 months of age were included. Accuracy (in percentage) of each consonant and vowel category produced by monolingual and bilingual children was compared. Results: The simultaneous KEB children produced consonants and vowels similar to ME children, but showed less accuracy compared to MK children. When English and Korean were compared, English stops and affricates were produced with higher accuracy than Korean counterparts by both monolingual and bilingual children. Conclusion: Phoneme production accuracy of simultaneous KEB children was affected by their language dominance. Furthermore, the size and complexity of phoneme category may play a role in phoneme accuracy; however, the effect of size and complexity on phoneme accuracy should also be understood relative to the order of speech acquisition.