Bilingual speakers show sensitivity to interlocutors’ L2 language proficiency during language production

Aims: The present study aimed to investigate if the mere presence of already-introduced task-irrelevant interlocutors would influence object naming in high-L2-proficient bilinguals. Methodology: Participants performed cued object naming in the presence of interlocutors who judged them as either high or low proficient in L2 (English). Before the main experiment, participants were familiarized with the interlocutors, after which they rated them as either high or low proficient in L2. During the two experiments, an interlocutor’s image appeared briefly, followed by the cued-object-naming task. In Experiment 1, the interlocutors were presented in blocks: high-L2-proficient, low-L2-proficient, and neutral interlocutors (the participants’ language proficiency was unknown). In Experiment 2, the interlocutors were presented in “pure” and “mixed” blocks. Data and Analysis: Naming latencies, switch cost, and mixing costs were analyzed using a mixed-effects model. Findings: In both experiments, participants incurred faster-naming latencies only when the interlocutor’s language proficiency was congruent with the language used for naming. The presence of interlocutors significantly altered the mixing costs and switch costs Originality: The current study explores how high-L2-proficient bilinguals employ different language control mechanisms in diverse language contexts induced by interlocutors with varied L2 proficiencies. Significance: The presence of these task-irrelevant interlocutors modulates proactive and reactive inhibitory control. The results provide evidence of dynamic adjustment in bilinguals’ language production as a function of interlocutors’ L2 proficiency.