Over the past several years, J.M. Annoni, a neurologist and professor at the University of Friborg (Switzerland), has conducted studies on the effects of bilingualism on the brain. In an interview published in the Swiss journal Le Matin, the specialist in language development shed light on the impact of second language acquisition and learning on the brain. How is the brain able to manage two (or more) languages?

The studies carried out by J.M. Annoni show just how flexible our brain can be, choosing between different strategies according to the context in which it is solicited. For example, a perfectly bilingual individual will tend to develop two ocular “reading modes” depending on whether the word to be read is in French or German. For French, the person’s eyes will tend to focus in the middle, while for German, they will tend to focus just before the beginning of the word. The suggested reasoning for the difference has to do with the relatively opaque nature of French (the same letter can be pronounced differently, making it necessary to see the entire word in order to know how to read it) as opposed to German (where each letter represents a sound). A language's structure can thus have an impact on how the brain reads.

Bilingual himself (French and Italian), J.M. Annoni explains that the monolingual and bilingual brain are nearly identical regardless of the language(s). A difference can however be seen when individuals learn a second language, for which the brain needs additional space. In this case, the brain solicits structures in the right hemisphere. But we’ve known for quite some time that language is largely concentrated in the left hemisphere (in key areas: Wernicke's area for understanding words, and Broca's area for speech production). Once this second language has been learned, this additional space is no longer “useful.” Using functional imaging, researchers identified a control system for inhibiting the unused language(s) when a person speaks. But this system isn’t actually specific to language, but to our actions in general.

In addition, brain organization varies depending on the age and manner in which a second language is acquired (immersion) or learned (at school). Indeed, a good command of a second language favors its automation, so the more fluent we become in a second the language, the more the brain uses the same structures solicited by the first language.

When it comes to the advantages of bilingualism, J.M. Annoni indicates that “being bilingual increases cognitive reserves, which fosters greater intellectual flexibility and brain plasticity.” But he adds that this optimization is just as effective in someone who develops a particular interest in any other domain. The neurologist also notes that the first signs of Alzheimer’s disease are generally slower to appear (from 6 months to 2 years) in bilinguals as compared to monolinguals.

And finally, the professor also goes against the popular misconception that there’s an age limit for learning a foreign language. On the contrary, the studies seem to show that, even late, this type of learning is still beneficial to the brain. He draws a comparison with practicing a musical instrument or any other kind of "stimulating" activity.