* <i>She Parle Beaucoup De Langues</i> : The Acquisition of Code‐Switching Constraints in L2 French

ABSTRACT The present study investigates the acquisition of code‐switching (CS) constraints in late L2 bilinguals in relation to their L2 proficiency and their experience with CS. L1‐English speakers who are acquiring L2‐French as adults completed an acceptability judgement task or an elicited production task to reveal whether they accepted or produced intra‐sentential CS in two syntactic positions where previous research has deemed it unlikely for bilinguals to code‐switch: PRONOUN‐VP and AUXILIARY‐VP. Acceptability data were analyzed using cumulative link mixed‐effects models, and production data were analyzed using mixed‐effects modeling. Regarding acceptability, despite little exposure to English‐French CS, the participants in the present study demonstrated having broadly acquired these two CS constraints at all levels of proficiency. Moreover, as L2 proficiency increased, sensitivity to the constraints against AUXILIARY‐VP and PRONOUN‐VP switches increased, suggesting that proficiency plays a crucial role in acquiring these constraints. Regarding elicitation, neither L2 proficiency nor CS experience was a significant predictor in constraint production, suggesting that this task measures a different part of bilingual competence. More broadly, the findings inform models of bilingual grammatical competence and have implications for bilingual education and assessment, supporting the view that CS is an integrated component of multilingual development.