The advantages of being bilingual are well known. Not only does bilingualism prove practical in a globalized world, but it also positively impacts intellectual growth and mental development, particularly in children. Now, new research even shows how learning a second language benefits the brain in old age, specifically in terms of protecting against Alzheimer’s disease.

Bilingualism contributes to changes in brain structure and may delay Alzheimer’s by as much as four and a half years, one study hypothesized. But a recent study relied on MRI data to look at brain regions associated with memory known to be affected by Alzheimer’s disease and mild cognitive impairment (MCI), as well as those areas responsible for language.

The experiment compared the brains and memory function of 34 multilingual participants with MCI; 34 monolingual participants with MCI; 13 multilingual participants with Alzheimer’s; and 13 monolingual participants with Alzheimer’s.

“In areas related to language and cognitive control, both multilingual MCI and Alzheimer’s disease patients had thicker cortex than the monolinguals,” the authors reported. “Our results contribute to the research that indicates that speaking more than one language is one of a number of lifestyle factors that contributes to cognitive reserve.”

Cognitive reserve is a concept referring to the brain’s ability to cope with challenges by finding alternative ways to complete a task. Multilingualism and its associated cognitive benefits, then, contribute to the brain plasticity, in which the brain can reroute or rewire itself.

This research also paves the way for future studies about how learning a second language benefits the brain.

“Our study seems to suggest that multilingual people are able to compensate for Alzheimer’s disease-related tissue loss by accessing alternative networks or other brain regions for memory processing,” said Natalie Phillips, a professor in the Department of Psychology at Concordia University in Quebec, Canada and research lead on the study. “We’re actively investigating that hypothesis now.”