Preschoolers’ Production of L2 Vowels Is Affected by Input Quality: A Longitudinal Study

We explore the impact of in-class input on pre-literate foreign language learners’ production of second-language (L2) English vowels, comparing vowels in words newly learnt in class from a near-native speaker of Standard Southern British English (SSBE), and earlier-learnt words heard from foreign-accented speakers. We further explore if and how classroom exposure to SSBE affects learners’ first-language (L1) vowels. Over 16 weeks, we recorded seven Moravian Czech preschoolers who attended weekly English lessons. They produced words with SSBE /i, ɪ, ɛ, æ, ʌ/ and Moravian Czech /iː, i, e, a/. We modelled normalised vowel height and retraction using linear mixed effects models. In newly learnt words, participants produced L2 /ɛ/ as higher than /æ/, showing greater separation of the vowels than in earlier-learnt words. Still, /ɛ, æ/ overlap was observed, with /æ/ showing great variability. Participants raised L2 /i/ in later recordings, producing /i/ and /ɪ/ similarly in earlier-learnt and newly learnt L2 words. L1 production was recorded twice approximately nine weeks apart. Participants raised L1 /iː/ and /i/, which became more similar in height and overlapped more with L2 /i/. L1 /e/ retracted and overlapped more with L2 /æ/; L1 /a/ retracted, assimilating to L2 /ʌ/. Our findings illustrate the influence of input characteristics on child learners’ production of L2 vowels and suggest that classroom input can drive phonetic drift in young children.