ESL learners’ intra-speaker variability in producing American English tense and lax vowels

Abstract

Nonnative (L2) English learners are often assumed to exhibit greater speech production variability than native (L1) speakers; however, support for this assumption is primarily limited to secondary observations rather than having been the specific focus of empirical investigations. The present study examined intra-speaker variability associated with L2 English learners’ tense and lax vowel productions to determine whether they showed comparable or greater intra-speaker variability than native English speakers. First and second formants of three tense/lax vowel pairs were measured, and Coefficient of Variation was calculated for 10 native speakers of American English and 30 nonnative speakers. The L2 speakers’ vowel formants were found to be native-like approximately half of the time. Whether their formants were native-like or not, however, they seldom showed greater intra-speaker variability than the L1 speakers.