Decoding how the cerebellum represents bilingual language information

While the cerebellum is increasingly recognized for its involvement in language processing, how it represents bilingual language information remains poorly understood. Crucially, it remains unknown whether and how it encodes bilingual information through activities and cortico-cerebellar interactions, as implicated by cortico-cerebellar loops, and whether the information richness varies across languages. Here, we used fMRI to investigate how the cerebellum flexibly adapts its contribution during narrative comprehension in proficient Chinese-English bilinguals. Specifically, we measured the informativeness of cerebellar activities and cortico-cerebellar interaction, indicating the degree to which neural features at a given moment are specific to the ongoing process. Participants performed identical tasks in their first (L1) and second language (L2). We revealed that cortico-cerebellar functional connectivity was highly informative for decoding narrative content. Notably, informativeness was greater in L2, indicating that L2 processing carries richer informational content consistently shared across individuals. Cross-language differences in cortico-cerebellar interactions-loaded informativeness were strongly associated with functional interactions related to the cortical default mode network (DMN) and cerebellar fronto-parietal network (FPN). These findings suggest that the cerebellum dynamically modulates its functional coupling with cortical networks to support language-specific processing, providing novel insights and a methodological framework for understanding its role in bilingual language processing. This study sheds light on the profile of the cerebellum during narrative processing in Chinese-English bilinguals in which the information carried by its connectivity with the cerebral cortex and the corresponding information compressibility varied across different languages.