The effect of listener dialect experience on perceptual adaptation to and generalization of a novel vowel shift

When adapting to novel vowel shifts, listeners rely on the systematicity of novel variants across vowel categories (e.g., parallel shifts), even when only part of a novel system is presented. We examined how a listener’s experience with components of a novel English front lax vowel backing shift impacts perceptual adaptation and generalization. First, listeners were exposed to no front lax vowels, shifted /ɪ/, shifted /ɪ æ/, or shifted /ɪ ɛ æ/. Then, listeners responded to items with shifted /ɪ ɛ æ/ in a lexical decision task. Listeners had varied dialect experience due to residential history. Westerners were experienced with /ɪ ɛ æ/ backing in the California Vowel Shift, Southerners were experienced with parallel movements of /ɪ ɛ/ but in another direction in the Southern Vowel Shift, and New Englanders were minimally experienced with front lax vowel shifts. Westerners and New Englanders endorsed more critical words in the /ɪ æ/ exposure condition than in the /ɪ/ exposure condition, consistent with a phonological feature theory of generalization, but Southerners endorsed fewer. Southerners’ lack of familiarity with /æ/ shifting in parallel with /ɪ ɛ/ inhibited perceptual adaptation and generalization, suggesting that dialect experience affects listeners’ perceptual processing of novel vowel shifts.