Non-native speakers’ acoustic variability in producing American English tense and lax vowels

Abstract

The primary goal of the present study was to compare native (L1) and non-native (L2) speakers’ vowel productions to determine whether the L2 subjects showed similar or greater within-subject (i.e., token-to-token) variability relative to the L1 talkers when producing American English vowels. We were particularly interested in whether L2 subjects whose vowels were more native-like would be less variable in their productions and whether L2 talkers’ whose vowels were less native-like would be more variable in their productions. First and second formants of the tense and lax vowel pairs / i—ɪ /, / e—ɛ /, and / u—ʊ / were measured and Coefficient of Variation was calculated for 10 native speakers of American English and 30 non-native speakers of English from three different language backgrounds (viz., 10 Mandarin speakers, 10 Korean speakers, and 10 Spanish speakers). Overall, the L2 subjects’ vowel formant patterns were found to be comparable to those of L1 speakers approximately half of the time. Whether the L2 talkers’ American English vowel formants were native-like or not, however, they seldom showed greater within-subject variability than the native speakers.