Learning foreign languages is associated with slower brain aging, with the protective effect increasing as more languages are mastered, according to researchers from Spain, Chile, Argentina, and Ireland. The findings were presented at the Federation of European Neuroscience Societies (FENS) Forum in Barcelona.

As people age, connections between neurons gradually weaken, contributing to declines in memory, processing speed, and other cognitive functions. The researchers set out to investigate whether multilingualism influences this process.

The study included 728 residents of the Basque Country, a region known for its high level of multilingualism. Using magnetoencephalography (MEG), the scientists recorded participants' brain activity and then trained an artificial intelligence algorithm to estimate the brain's "biological age" based on the integrity of neural connectivity. The model was subsequently validated in an independent cohort of 144 individuals who spoke one, two, three, or four languages.

The analysis showed that the brains of bilingual participants appeared, on average, six years younger than those of monolingual individuals. Among people who spoke three languages, the difference increased to approximately seven years, while participants fluent in four languages exhibited brains that appeared up to 13 years younger.

The researchers also found that the benefits were influenced not only by the number of languages spoken but also by the level of proficiency and the age at which the second language was acquired. Earlier language learning and greater fluency were associated with a more youthful pattern of neural connectivity.

According to the authors, regularly using multiple languages provides continuous cognitive stimulation by requiring the brain to switch between linguistic systems, suppress irrelevant information, and engage attention, memory, and executive control processes more intensively. This ongoing "mental workout" may help preserve neural connections and slow age-related changes in the brain.

The researchers emphasize, however, that the study demonstrates an association rather than a cause-and-effect relationship. Other factors—including education, lifestyle, reading habits, musical training, and social engagement—may also have contributed to the findings. Nevertheless, the results support the idea that multilingualism may be one of several factors that help preserve cognitive health in later life.