Language Dominance and Performance Outcomes in Bilingual Pronunciation

A significant body of experimental and naturalistic studies has demonstrated that bilingual speakers of Romance language–English pairings are capable of creating separate phonetic categories for the production of voiceless stops, measured as voiced onset time (VOT), across their languages (Caramazza, Yeni-Komshian, Zurif & Carbone, 1973; Flege & Eefting, 1987: Major, 1992, interalia). However, bilinguals equally tend to show altered, either converged or exaggerated VOT values in one or both of their languages relative to the those of monolingual speakers. Sancier and Fowler’s (1997) case study of a Portuguese-English bilingual suggests that a bilingual’s VOT values are not fixed; rather they tend to drift according to the ambient speech environment. They label the phenomenon observed in their study as “gestural drift” because the gradient changes to VOT are observed in both the speaker’s L1 (Portuguese) and L2 (English). Gestural drift is consistent with Grosjean’s (2001) notion of “language mode” and with Escudero and Boersma’s (2002) “perceptual mode.” Such research contends that bilinguals’ language use is malleable in that they may behave differently according to which language they are producing or perceiving at a given time. The focus of the present study is to examine the effect of language mode on VOT production in real time via the use of a linguistic code-switching task. As code-switching arguably requires bilinguals to activate both languages simultaneously, it is expected that speakers should manifest VOT values in code-switched tasks that differ significantly from their productions in monolingual modes. At issue is the extent to which each of a bilingual’s component languages is affected by code-switching. Gestural drift implies that they should be equally vulnerable to inter-linguistic influence. But if phonetic categories are established early in childhood then we would expect that bilinguals’ L1 categories should be resistant to incursions from the L2 but not vice-versa.