When research began on brain patterns and impulses among bilinguals, an interesting and unexpected dichotomy emerged. Researchers were surprised to find that how a second language is learned, and where the “data” is “stored” in the brain, depends on the age of the bilingual.
It was observed that all children, if given the appropriate environment of exposure, could learn multiple languages with relative ease. The child brain is specifically designed for rapid acquisition and assimilation of linguistic information and principles. Therefore, in the developmental stage a child could conceivably learn as many languages as they are consistently exposed to.
When scanning the brains of such bilinguals, we find that all of the “language banks” are superimposed in the same region of the brain (the language centers in the left hemisphere of the brain, where language neurons reside for all monolinguals as well). This means that the child bilingual activates only one region of the brain to process and transmit linguistic data.
The real surprise came when child bilinguals were compared to people who had learned a second language later in life (adult-onset bilinguals). Unlike their more youthful counterparts, adult bilinguals consistently store sound banks for their second language (their acquired language), in the right hemisphere of the brain, a completely separate location.
As a result of this separation, adult-onset bilinguals have a unique, if modest, edge over monolinguals when it comes to cognitive function and defense against age related mental decline (dementia and Alzheimer’s disease). This is because the separation increases communication and cooperation between the left and right hemispheres of the brain. This strengthens the bilingual’s cognitive performance, by encouraging the recruitment and coordination of different centers of the brain, which is the very definition and essence of cognitive reserve associated with neuroplasticity.
Although adults and children process and store the linguistic information differently, it’s clear that we all benefit from learning new things throughout life, regardless of age.