The role of audiovisual modality in predicting the neurodynamics of language control in Tibetan–Chinese bilinguals

Although bilinguals use both auditory and visual cues, the cognitive cost of language switching in audiovisual contexts is unclear. We investigated the cost in Tibetan–Chinese bilinguals using a task with audiovisual, visual and auditory modalities. In Study 1, the audiovisual modality yielded the fastest reaction times, reflecting improved processing efficiency. ERP data revealed smaller positive amplitudes in the early window (200–350 ms) for audiovisual modality, indicating reduced neural demand, while only auditory modality showed significant divergence in the later window (350–700 ms). Moreover, audiovisual context, L2-to-L1 switching and early neural responses predicted switching behavior. Study 2 replicated the behavioral and ERP findings of Study 1 and demonstrated that auditory input and second-language processing exacerbated switch costs. These findings shed light on multisensory integration in language switching by demonstrating that audiovisual cues reduce switch costs, whereas auditory input and second-language processing exacerbate them, with implications for language education and cognitive interventions.