Early linguistic experience shapes bilingual adults’ hearing for phonemes in both languages

Abstract

How do bilinguals represent category structure for phonemes in early acquired languages? /b/ and /p/ voice onset times (VOTs) are earlier and closer together in English than in Mandarin. Hence the category boundary and the steepness of the transition can show ‘tuning’ to language-specific acoustic structure (i.e., earlier boundary and steeper slope for English). As preregistered, we mapped identification functions of early English-Mandarin bilingual adults (N=66) on a /b/ - /p/ VOT continuum in each language. Individual bilingual-balance was derived using principal component analysis and entered into GLMMs of categorical boundary and slope. As predicted, VOTs were earlier for English than Mandarin. Early bilingual-balance predicted the slope of the transition between categories: Those who heard more English from an earlier age showed steeper slopes than those who heard more Mandarin. Findings are consistent with discrete representations for each language, and transfer of category structure from the earlier acquired language.