A Study on VOT of Initial Stops in English Produced by Korean, Thai and Chinese Speakers as L2 Learners

The present paper examines phonetic characteristics of the initial stop consonants of English uttered by ESL learners whose native tongues are Korean, Thai, and Mandarin Chinese. It examines VOT (voice onset time) values of initial stops in the three languages and compares them with those of English stops produced by ESL learners of the three languages. From the acoustic analysis, it can be said that the voicing contrast of initial stops in Korean, Thai, and Mandarin Chinese is distinguished by a timing dimension of VOT, and that the ESL learners of these languages tend to use their stop categories to produce voicedvoiceless categories of English stops. Among three language groups, however, Korean ESL learners produce English voiceless stops with VOT values that are intermediate to those of their lax and aspirated stops. Thai and Chinese ESL learners tend to use their L1 voicing contrasts to produce the voicing contrast of English stops. Proximity in VOT values can be considered to be one of the main cues of using their L1 stop categories in learning L2 categories.