People who speak two or more languages appear shielded from accelerated ageing, an international team of neuroscientists has said, announcing research findings that bolster evidence for the protective effects of multilingualism.

Their study has found that people who use only one language are twice more likely to experience accelerated ageing, measured through their bio-behavioural age gap — the difference between a person’s chronological age and biological age.

Each additional language strengthens the protective effect, the results have suggested. One extra language lowered the risk of accelerated ageing by about 9 per cent, two lowered it by 20 per cent, and three by 29 per cent.

A person’s biological age is calculated from cognitive and functional abilities, cardiovascular and metabolic health, physical activity levels and sensory capabilities, among other factors. A positive age gap indicates accelerated ageing and a negative gap reflects delayed ageing.

For instance, a 48-year-old with a biological age of 52 is ageing faster, while a biological age of 45 years indicates slower ageing.

“Our study answers a question that had never been tested before with direct measures: does multilingualism slow down ageing?” neuroscientist Lucia Amoruso at the Basque Centre on Cognition Brain and Learning in Spain told The Telegraph over email.

Earlier evidence for multilingualism had emerged from research showing delayed dementia and context-specific advantages, including better post-stroke recovery, without direct measures of ageing itself.

Amoruso and her colleagues analysed the language-speaking practices of 86,149 people aged 51 to 90 from 27 European countries, accounting for multiple physical, functional capabilities, myriad health parameters and socio-economic factors that could affect the bio-behavioural age gap.

“Multilingual individuals tend to follow healthier, slower-ageing trajectories,” Amoruso said. The pattern remained after the researchers considered education, income and other factors that could influence ageing.

The findings were published in the journal Nature Ageing on Monday.

The researchers say the effect was consistent across the 27 countries, suggesting that the benefits of multilingualism may extend to other regions.

“This effect could be even more pronounced in India where intrinsic multilingualism is deeply embedded in daily life, education and culture,” Augustin Ibanez, professor at the Global Brain Health Institute, Trinity College in Dublin, Ireland, who led the study, told this newspaper.

In India, the constant need to switch between languages and navigate diverse
linguistic environments might amplify cognitive and social advantages observed in Europe, Ibanez said.

“These findings have implications for India,” said Nandini Singh, a neuroscientist and psychology professor at Ashoka University in Sonipat, Haryana, who was not involved in the European study. “We would like to probe multi-literacy — not just speaking but reading and writing in multiple languages — which we hypothesise could similarly offer protective effects.”

About a decade ago, medical researchers at the Nizam Institute of Medical Sciences in Hyderabad found that bilingual patients recovering from strokes often achieved better intellectual outcomes than monolingual patients.

Their five-year analysis of 608 stroke patients showed that speakers of two languages were twice as likely to regain full intellectual function and performed better in tests of attention and information retrieval than monolinguals.

Scientists believe multilingualism’s effects emerge through multiple levels. People who use several languages show lower chronic stress and inflammation, better cardiovascular and metabolic functions, and more efficient brain networks that typically decline with age.

And socially, multilingualism broadens communication networks, enhances intercultural engagement and reduces isolation — all factors linked to longer, healthier lives, Ibanez said.

However, context also matters, Amoruso said. “When we adjusted for immigration patterns, the protective effect of speaking multiple languages disappeared,” she explained.