Sixteen American‐English vowels including 12 monothongs and 4 diphthongs were recorded in a phonetic context of /hvd/ from young English, Chinese, and Korean talkers. The Chinese and Korean talkers were bilingual and had stayed in US from 6 months to 6 years. Results of acoustic analysis showed that there was no significant difference in F1×F2 vowel space among the three groups of talkers. In addition, the three groups of talkers showed great similarity in F2/F1 ratio across the 12 monothongs. Vowel durations had significantly greater variability across vowel categories for the Chinese and Korean talkers than for the English talkers, indicating that, besides producing spectral differences among vowels, Chinese and Korean talkers also attempted to generate durational difference among vowels to make each vowel distinguishable from others. More acoustic features such as spectral tilt and formant transition in the diphthongs will be discussed as well as the effects of the second language experience.