Two co-activated grammars, one brain: Adverb placement processing of English–French bilinguals

Abstract The shared-syntax argument of bilingual language representations has support from studies of cross-linguistic structural priming. However, more research needs to be conducted to support the grammatical co-activation hypothesis. The current study investigates the behavioral patterns of bilingual grammatical co-activation in comprehension, taking into account the age of immersion (AoI), which significantly affects the performance of bilinguals. Specifically, we tested 114 native speakers of English: 84 English–French bilinguals (53 early and 31 late learners of French) and 30 functional English monolinguals with a grammatical maze task using English stimuli manipulated with the two opposing English and French rules of adverb placement. Early bilinguals with an AoI earlier than 7 appear to be more accepting of the French adverb placement while reading English sentences. This suggests that earlier bilinguals are more likely to show co-activation (and competition) of the two languages. Results support the shared-syntax system of bilingual grammatical representations.