What did the researchers actually find?

The comparison between actual age and estimated brain age revealed a striking pattern:

• Two languages: brains appeared about 6 years younger than those of monolinguals
• Three languages: about 7 years younger
• Four languages: roughly 13 years younger

Dr. Amoruso said: "In simple terms, people who spoke more languages tended to have brains that looked younger than expected for their chronological age. The effect was not only related to the number of languages spoken. Higher language proficiency and earlier acquisition of a second language were also associated with more delayed brain aging. This suggests that multilingual experience matters as a gradient: it is not simply about being bilingual or not, but about the depth and duration of language experience."

How solid are these results?

The findings are preliminary in an important sense: they come from a conference presentation rather than a peer-reviewed publication, and the study has real limitations. The researchers adjusted their analysis for age, sex and education. Still, they cautioned that other influences on brain health, including lifestyle and social engagement, could also explain part of the differences they observed.

In other words, multilingual people may differ from monolinguals in ways beyond language itself. People who learn several languages may also be more socially active or cognitively engaged, factors already known to support brain health.

The team had previously published research suggesting that people living in countries where multilingualism is common may age more slowly, and the new work extends that line of inquiry to individual language experience.

Could language learning protect against dementia?

The next steps for Dr. Amoruso and her colleagues point in two directions. They want to investigate whether similar patterns appear in people with neurodegenerative conditions such as Alzheimer's disease, where brain aging and resilience matter most.

They also hope to explore whether speaking closely related languages, such as Spanish and Basque, could produce an even stronger effect. The reasoning: switching between similar languages may demand greater mental control, because speakers must continually manage competing words and overlapping language systems.

Professor Christina Dalla of the National and Kapodistrian University of Athens, who chairs the FENS Forum communication committee and was not involved in the research, placed the findings in a broader context. She noted that many factors influence brain health with age, including not smoking, eating well, and social, artistic and physical activity.

"This study suggests that learning a second, third or fourth language could help our brains to stay younger for longer, and the earlier we start, the better," Professor Dalla said. "There are many good reasons for learning another language at any age — social, cultural and for the health of your brain — so we should support language learning at school and throughout life, even if it's hard."

The research received funding from the National Institutes of Health, the National Institute on Aging, the Fogarty International Center, the Multi-partner Consortium to Expand Dementia Research in Latin America (ReDLat), the Alzheimer's Association, the Global Brain Health Institute, the Davos Alzheimer's Collaborative, Alzheimer's Society UK, FONDECYT, and a Ramón y Cajal fellowship through the Spanish State Research Agency.