The effect of native language on the second language vowel variability
Jaekoo Kang, D. H. Whalen, Hosung Nam · The Journal of the Acoustical Society of America · 2018
Korean learners of English must create four vowel categories for English (/i, ɪ/ and /ɛ, æ/) in relation to two similar native categories (/i/ and /ɛ/). It is hypothesized that new categories should be easier to learn than similar ones (Flege, 1994), but it is unclear whether the English L2 vowels are similar or new. The degree of similarity between the four English vowels and the two Korean vowels was examined using the distribution metrics (i.e., ellipse overlap, cross-entropy, and Gaussian Mixture Model) as well as Euclidean distance in F1/F2 space. The L2 spoken corpus included 100 repetitions of words in both Korean and English spoken by 37 Korean L2 learners (20 female). Preliminary results indicate that the English (L2) high vowel pair was more overlapped with Korean /i/ than the low vowel pair with Korean /ɛ/, especially for male speakers. For the English (L2) low vowel pair, female speakers showed less overlap but higher variability along F1 direction than male speakers. This demonstrates that the similarity between Korean and English vowels is characterized by the distribution as well as the distances between the vowel categories. Acoustic results will be further compared with identification by native English speakers.