Learning a second language around age 10 can boost brainpower.

Researchers found that people who began learning English around age 10, meaning they heard and used it in daily life, showed improvements in the structure of the brain's white matter compared to people who grew up speaking only English and did not learn a second language. These higher levels of structural integrity were seen in areas responsible for language learning and semantic processing.
Study lead, Christos Pliatsikas of the University of Kent School of Psychology, said, "Everyday handling of more than one language, functions as an intensive cognitive stimulation that benefits specific language-related brain structures by preserving their integrity, and therefore it protects them against deterioration in older age."
Source-Medindia