The Journal of Studies in Language 29.2, 323-343. This study explores the dynamic formant transitions of the American English vowels [ei] and [ou] produced by native American English speakers (Group E), Korean-English bilingual speakers (Group KE), and Korean learners of English (Group K). The speakers read “bait [beit]” and “boat [bout]” within a carrier sentence. The average distance of the formant movements was similar between Groups E and KE, but overall longer for Group K than E. The measurement point showing the minimum F2 value for [ou] was earlier for Group K than for Groups E and KE. In addition, while Groups E and KE showed similar ranges of the formant movements for [ei] and [ou], Group K started from higher F1s for the vowel [ei] and displayed lower F1s and F2s (i.e. produced higher and more back vowels) across the vowel [ou] compared to Group E. As for vowel duration, Group E displayed the shortest durations, and Group K, the longest. The overall data indicated that there is an effect of foreign language experience in learning the dynamic transition patterns of vowels as well as their steady-state values. (Ewha Womans University)