fMRI scans of 151 participants showed that bilingual people had better connectivity between brain regions, especially if they learned their second language at a younger age. This effect was especially strong between the cerebellum and the left frontal cortex

>Scientists recruited 151 participants who either spoke French, English, or both languages, and recorded the age at which they learned their second language. The participants were scanned using resting state functional magnetic resonance imaging (fMRI) to record whole-brain connectivity, rather than focusing on specific regions as was done in previous bilingualism studies.
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>fMRI scans revealed that bilingual participants had increased connectivity between brain regions than monolingual participants, and this connectivity was stronger in those who learned their second language at a younger age. This effect was particularly strong between the cerebellum and the left frontal cortex.
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>The results mirror previous studies which have shown that brain regions do not work in isolation, but interact with others to understand and produce language. Research has also shown that whole-brain efficiency aids cognitive performance.
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>This latest study reveals more about how bilingualism influences the brain connections we use to think, communicate and experience the world around us.

Paper: [Enhanced efficiency in the bilingual brain through the inter-hemispheric cortico-cerebellar pathway in early second language acquisition | Communications Biology](https://www.nature.com/articles/s42003-024-06965-1)