Inter-language interference in VOT production by L2-dominant bilinguals: Asymmetries in phonetic code-switching

Speech production research has demonstrated that the first language (L1) often interferes with production in bilinguals' second language (L2), but it has been suggested that bilinguals who are L2-dominant are the most likely to suppress this L1-interference. While prolonged contextual changes in bilinguals' language use (e.g., stays overseas) are known to result in L1 and L2 phonetic shifts, code-switching provides the unique opportunity of observing the immediate phonetic effects of L1–L2 interaction. We measured the voice onset times (VOTs) of Greek–English bilinguals' productions of /b, d, p, t/ in initial and medial contexts, first in either a Greek or English unilingual mode, and in a later session when they produced the same target pseudowords as a code-switch from the opposing language. Compared to a unilingual mode, all English stops produced as code-switches from Greek, regardless of context, had more Greek-like VOTs. In contrast, Greek stops showed no shift toward English VOTs, with the exception of medial voiced stops. Under the specifically interlanguage condition of code-switching we have demonstrated a pervasive influence of the L1 even in L2-dominant individuals. ► Previously, Greek–English bilinguals produced VOTs indistinguishable from monolinguals. ► When asked to produce the same stops via a code-switch, the VOTs were affected. ► There was an asymmetry in that the bilinguals' dominant L2 was affected more than the L1. ► Demonstrates a pervasive influence of the L1 even in L2-dominant individuals. ► Suggests bilinguals' two phonological systems are not separate, even in speakers who match monolinguals.