A study of language and cognition in older adults using a national survey

Petrosyan et al. (2025) studied this impact with a sample of 4088 older Indian adults ages 60 or over, which included around half without formal schooling (54%). This sample was procured from the Longitudinal Aging Study in India – Diagnostic Assessment of Dementia, which is a subset of a national survey representing 40 different languages and dialects. Two main findings from this study were:

• Multilingualism was associated with better cognitive function across all studied domains among those with education; the relatedness between languages was not a factor here
• Among those without education, however, multilingual adults who spoke related languages had better executive function compared to monolinguals

In this study, we see that language diversity and education may both affect cognitive functioning among older adults. What does this mean for multilingual benefits? It may mean relatedness of languages spoken by the multilingual speaker may affect how the brain organizes, retrieves, and processes information. Through the study’s analysis, teasing apart the differences between those with and without education revealed a sort of cost-benefit model of speaking related vs unrelated languages; based on their finding, speaking unrelated languages did not confer better executive function for those in the non-education group. The authors point out that those in the non-education group may have reduced resource access and may use related languages more often than unrelated ones since related languages are present in similar geographical areas (Petrosyan et al., 2025). From this we can see that:

• Education levels may also indicate resource availability (Petrosyan et al., 2025), not only skill/knowledge acquisition levels
• Related languages may be found in related geographical areas (i.e., languages spoken become more different as geographic distances increase; Huisman et al., 2019)
• More use of languages (as may have been the case in related languages) may confer clearer cognitive benefits than less-used languages

So, is multilingualism helpful or… ?

This brings us to question of what multilingualism is. Is multilingualism defined simply by the languages known or also by its language diversity, or even its proficiency? Defining multilingualism does not appear consistent among multilingual studies, making it prudent to parse out its variations to understand its truer effects on our thinking. Multilingualism may indeed keep our cognitive control with age, but its caress may come with caveats.

References

Amoruso, L., Hernandez, H., Santamaria-Garcia, H., Moguilner, S., Legaz, A., Prado, P., Cuadros, J., Gonzalez, L., Gonzalez-Gomez, R., Migeot, J., Coronel-Oliveros, C., Cruzat, J., Carreiras, M., Medel, V., Maito, M. A., Duran-Aniotz, C., Tagliazucchi, E., Baez, S., García, A. M., & Ibanez, A. (2025). Multilingualism protects against accelerated aging in cross-sectional and longitudinal analyses of 27 European countries. Nature aging, 5(11), 2340–2354. https://doi.org/10.1038/s43587-025-01000-2

Bialystok, E. (2021). Cognitive Implications of Bilingualism. Oxford Research Encyclopedia of Psychology. https://doi.org/10.1093/acrefore/9780190236557.013.763

Huisman, J. L. A., Majid, A., & van Hout, R. (2019). The geographical configuration of a language area influences linguistic diversity. PloS one, 14(6), e0217363. https://doi.org/10.1371/journal.pone.0217363

Petrosyan, S., Strangmann, I. M., Nichols, E., Meijer, E., Briceño, E. M., Narayanan, S., Lee, J., & Arce Rentería, M. (2025). The association of multilingualism with diverse language families and cognition among adults with and without education in India. Neuropsychology, 39(3), 223–234. https://doi.org/10.1037/neu0000988

One such area is in brain aging, where bilingualism or multilingualism has shown to confer some protection on our cognition. Cognition is what we call our process of learning, experiencing, and thinking (Bayne et al., 2019) and is an area language researchers explore to gauge the effects of languages on our thoughts, thinking, and memories. As with many things, cognition is subject to the less pleasant aspects of aging.

Yet, cognitive reserve, a feature of cognition, is one that may be bolstered by one’s use of languages. Cognitive reserve can be described as the buffer between an intangible thinking and a physical brain that can sustain some cognitive function, despite a crumbling of physical mass. Knowing more than one language, as is in the case of bilingualism, can support cognitive reserve into old age and improve performance compared to those who speak one language (Bialystok, 2021). Bilingualism in earlier life stages may even create a cognitive protective effect that endures into old age (Ballarini et al., 2023). This is concluded from results on tasks or activities and/or through brain structure itself.

How do we measure cognition?

Cognitive tests and tools are used to measure different mental activities, like memory

How do we SEE the brain?

Brain activity and structures can be measured through brain scans, like those of functional Magnetic Resonance Imaging, or fMRI

An area of the brain that is of interest for neurological and language researchers alike is the hippocampus. Known for its role in memory, the hippocampus may also receive protection from bilingualism since hippocampal volume may increase with bilingualism (Voits et al., 2022). Though this is delightful news and there is much showing us the vigour of multiple language use, there are still inconsistencies in the research where some studies show little evidence for multi-language-based neuroprotection (Weyman et al., 2020; Gard et al., 2025). In the Gard et al. (2025) study, for example, older adult monolinguals did better than their bilingual counterparts on language tasks, but not on tasks that measured executive function.

What is executive function?

Executive function refers to how we manage our thinking, including its flexibility and control

All research comes with caveats, but ultimately evidence builds for bilingual and multilingual-based cognitive benefits. Some may see the smallness of samples as a limitation, which it very well is, but recent technologies have increased connectivity among research communities, allowing for larger and more diverse participant samples to coalesce. With a sample of over 85,000 participants across 27 countries (albeit European countries), a recent study provides strong support for multilingualism being a protective factor in aging and monolingualism increasing accelerated aging (Amoruso et al., 2025).

Like the foods we eat and the moves we make, language is another facet of our existence that inspires it.

© T. Y. Giri

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References

*Please note: References are not fully formatted.

Amoruso, L., Hernandez, H., Santamaria-Garcia, H., Moguilner, S., Legaz, A., Prado, P., Cuadros, J., Gonzalez, L., Gonzalez-Gomez, R., Migeot, J., Coronel-Oliveros, C., Cruzat, J., Carreiras, M., Medel, V., Maito, M. A., Duran-Aniotz, C., Tagliazucchi, E., Baez, S., García, A. M., & Ibanez, A. (2025). Multilingualism protects against accelerated aging in cross-sectional and longitudinal analyses of 27 European countries. Nature aging, 5(11), 2340–2354. https://doi.org/10.1038/s43587-025-01000-2

Ballarini, T., Kuhn, E., Röske, S., Altenstein, S., Bartels, C., Buchholz, F., Buerger, K., Dechent, P., Dobisch, L., Ewers, M., Fliessbach, K., Freiesleben, S. D., Frommann, I., Gabelin, T., Glanz, W., Görß, D., Haynes, J. D., Incesoy, E. I., Janowitz, D., … Wagner, M. (2023). Linking early-life bilingualism and cognitive advantage in older adulthood. Neurobiology of Aging, 124, 18–28. https://doi.org/10.1016/j.neurobiolaging.2022.12.005

Bayne, T., Brainard, D., Byrne, R. W., Chittka, L., Clayton, N., Heyes, C., Mather, J., Ölveczky, B., Shadlen, M., Suddendorf, T., & Webb, B. (2019). What is cognition? Current Biology, 29(13), R608–R615. https://doi.org/10.1016/j.cub.2019.05.044

Bialystok, E. (2021). Bilingualism: Pathway to Cognitive Reserve. Trends in Cognitive Sciences, 25(5), 355–364. https://doi.org/10.1016/j.tics.2021.02.003

Gard, S., Saad, J., Sheppard, C. L., & Taler, V. (2025). Monolinguals Outperform Bilinguals in Language but Not Executive Function in Aging and Cognitive Impairment. Neuropsychology, 39(8), 781–790. https://doi.org/10.1037/neu0001028

Voits, T., Robson, H., Rothman, J., & Pliatsikas, C. (2022). The effects of bilingualism on hippocampal volume in ageing bilinguals. Brain Structure and Function, 227(3), 979–994. https://doi.org/10.1007/s00429-021-02436-z

Weyman, K. M., Shake, M., & Redifer, J. L. (2020). Extensive Experience with Multiple Languages May Not Buffer Age-Related Declines in Executive Function. Experimental Aging Research, 46(4), 291–310. https://doi.org/10.1080/0361073X.2020.1753402