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Benefits of a Bilingual Brain

¹ Language ability is typically measured in two active parts, speaking and writing, and two passive parts, listening and reading. While a balanced bilingual has near equal abilities in two languages, most bilinguals around the world know and use their languages in varying proportions. But recent advances in brain imaging technology have given neurolinguists a glimpse into how specific aspects of language learning affect the bilingual brain. 

² It's well known that the brain's left hemisphere is more dominant and analytical in logical processes, while the right hemisphere is more active in emotional and social ones, though this is a matter of degree, not an absolute split. The fact that language involves both types of functions has led to the critical period hypothesis. According to this theory, children learn languages more easily because the plasticity of their developing brains lets them use both hemispheres in language acquisition, while in most adults, language is lateralized to one hemisphere, usually the left. If this is true, learning a language in childhood may give you a more holistic grasp of its social and emotional contexts. 

³ Conversely, recent research showed that people who learned a second language in adulthood exhibit less emotional bias and a more rational approach when confronting problems in the second language than in their native one. But regardless of when you acquire additional languages, being multilingual gives your brain some remarkable advantages, such as higher density of the grey matter that contains most of your brain's neurons and synapses, and more activity in certain regions when engaging a second language. The strong workout a bilingual brain receives throughout its life can also help delay the onset of diseases, like Alzheimer's and dementia by as much as five years.

Source: Adapted from “Benefits of a bilingual brain” (Video), by Mia Nacamuli for TED-ed, 2015. Available on: https://www.youtube.com/watch?v=MMmOLN5zBLY with subtitles.