First and second language vowel perception in early bilinguals

Abstract

Previous research has shown that the perception of speech sounds is stronglyinfluenced by the internal structure of maternal language categories. Specifically,it has been shown that stimuli judged as good exemplars of a phonemiccategory are more difficult to discriminate from similar sounds than badexemplars from equally similar sounds. This effect seems to be restricted tophonemes present in the maternal language, and is acquired in the first monthsof life. The present study investigates the malleability of speech acquisition byanalysing the discrimination capacities for L2 phonemes in highly proficientSpanish-Catalan bilinguals born in monolingual families. In Experiment Isubjects were required to give goodness of fit judgments to establish the bestexemplars corresponding to three different vowel categories (Catalan /e/ and/ε/ Spanish /e/). In Experiments 2 and 3, bilinguals were asked to perform adiscrimination task with materials in their maternal language (Exp. 2) and intheir second language (Exp. 3). Results reveal that bilinguals show a reduceddiscrimination capacity only for good exemplars of their maternal language,but not for good exemplars of their second language. The same pattern ofresults was obtained in Experiment 4, using a within-subjects design and abias-free discrimination measure (d'). These findings support the hypothesisthat phonemic categories are not only acquired early in life, but under somecircumstances, the acquisition of new phonemic categories can be seriouslycompromised, in spite of early and extensive exposure to L2.