How do you say "protect me against dementia" in Hindi? It might be worth learning. A new study shows how bilingualism can ward off cognitive decline and dementia.
Scientists in India and the United Kingdom found that the bilingual patients enrolled in a study of people with dementia developed their disease on average 4.5 years later compared to patients who spoke only one language.
These results applied to three kinds of dementia, including Alzheimer's disease, and were independent of patients' educational background or income. The study appears today (Nov. 6) in the journal Neurology.
While the patients in this study were not representative of everyone — they lived in India, which has a deep culture of multilingualism — the researchers said the results could be applicable to some degree to anyone who speaks or is learning a second language.
"Bilingualism can't obliterate" the risk of dementia, said Dr. Thomas Bak of the University of Edinburgh, a co-author of the new study, "but it can delay significantly its onset."
Tower of Babel is good
The Indian study, led by Suvarna Alladi of Nizam's Institute of Medical Sciences in Hyderabad, India, is the largest to date on language acquisition and dementia. The researchers examined 648 people with an average age of 66 who were diagnosed with dementia. Among them, 240 had Alzheimer’s disease, 189 had vascular dementia (a decline in thinking skills due to reduced blood flow to the brain), and 116 had frontotemporal dementia (dementia affecting primarily the brain's frontal or temporal lobe), with the remainder having mixed dementia.
Nearly 400 patients spoke two or more languages, as is common in India, and many were illiterate. Across the board, those speaking a second language developed dementia later than those speaking only one language. There was no additional benefit in speaking more than two languages, though. [6 Foods That Are Good For Your Brain]
The study provides the best evidence to date that merely processing a second language — independent of wealth and education and the health benefits they often secure — offers a protective benefit to the brain.
"Our study is the first to report an advantage of speaking two languages in people who are unable to read, suggesting that a person's level of education is not a sufficient explanation for this difference in dementia prevalence seen in other studies, Alladi said.
Bak likened what learning a language does for the brain to what swimming does for the body. All physical activity is good for the body, but swimming is particularly good at providing a balanced workout, with fewer injuries. Similarly, language — compared to puzzles, reading and other activities — provides a thorough brain workout. When switching from one language to another, the brain must process different words and sounds and often must work in an entirely different setting in terms of syntax and social norms, which taps into numerous brain regions.
Never too late?
"In India, you learn languages from the streets at an early age, from neighbors and the children of neighbors and so on," Bak told LiveScience. In the United States and Europe, most people usually learn a second language at school, he said. So, would this still help ward off dementia?
"I am optimistic, and would say it is never too late" to learn another language in order to benefit from it cognitively to some degree, Bak said.
Bak added that certain groups in the United States actually might be similar to those he studied in India — for example, some Hispanics in bilingual homes and others who learn two languages informally yet fluently.
Nevertheless, Bak and Alladi said the nature and timing of a person's learning of a second language in relation to dementia are key questions they would like to answer in future studies.
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Christopher Wanjek is a Live Science contributor and a health and science writer. He is the author of three science books: Spacefarers (2020), Food at Work (2005) and Bad Medicine (2003). His "Food at Work" book and project, concerning workers' health, safety and productivity, was commissioned by the U.N.'s International Labor Organization. For Live Science, Christopher covers public health, nutrition and biology, and he has written extensively for The Washington Post and Sky & Telescope among others, as well as for the NASA Goddard Space Flight Center, where he was a senior writer. Christopher holds a Master of Health degree from Harvard School of Public Health and a degree in journalism from Temple University.