One thing I've never seen discussed on this topic (possible I just missed it, I only read popular accounts) is whether speaking multiple languages is a proxy for higher sociability / stronger social ties. That's a known dimension that improves health and aging and I wonder if just being able or interested in speaking with a broader swath of people is what helps more than the cognitive demands of switching.

Sadly, this beneficial activity doesn’t look promising in the longterm. Real-time interpretation of foreign languages through earbuds is already available in its nascent phase, and China at least has begun cutting foreign-language programmes at its unis because such AI translation is seen as the way of future. Once this tool becomes adopted enough societally, the learning of foreign languages is going to become a very niche hobby. It’s already becoming a niche hobby when many developed-country Gen Z are content with traveling and working abroad with only a knowledge of English alongside their native language.

Some peer criticism from: Vanhove, J. (2026). Does multilingualism really protect against accelerated ageing? Critical comments on Amoruso et al. (2025). Journal of Multilingual and Multicultural Development, 1–10.

"As the authors correctly point out in their discussion, their observational study does not allow them to establish any causal links between the degree of multilingualism in a country and the extent to which its inhabitants show signs of accelerated ageing. Unfortunately, they do not seem to have kept this insight in mind when they came up with the title (‘Multilingualism protects …’) and the abstract (‘These results underscore the protective role of multilingualism …’) that grabbed the media's attention."

"The authors use country-level data on multilingualism, namely the estimated percentage of monolinguals in the country (the Mono variable in BAG_OR_cross.csv), the estimated percentage of people in the country who know exactly one additional language (One), those who know exactly two additional languages (Two), and those who know at least three additional languages (Three), always at the time of data collection."

"According to a simple OLS regression model at the country level with the monolingualism percentage as its sole predictor, a 10-percentage-point difference in monolingualism is associated with a difference in the average GAP value of about 0.36 years (some 133 days; 95% CI: (58,207) days). If log-per-capita GDP is controlled for, a 10-percentage-point difference in monolingualism is associated with a difference in the average GAP value of about 0.29 years (some 105 days; 95% CI: (22,188) days)."

> 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 ageing. 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.”

https://www.fens.org/news-activities/news/speaking-another-l...