More evidence that bilingualism delays dementia

Speaking two languages can delay the onset of dementia, but knowing three or more languages may not provide any extra benefit for maintaining the mind.

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Speaking two languages may keep the mind sharp longer than knowing only a single language, even in those who can’t read.

Scientists reviewed the records of 391 bilingual and 257 monolingual patients diagnosed with dementia between 2006 and 2012 at a clinic in Hyderabad, India. Patients who spoke two languages developed the first signs of dementia an average of 4.5 years later than people who only spoke one language.

Additional results suggest that education alone cannot account for the difference. Bilingual speakers who could not read developed dementia an average of 6 years later than single-language speakers, the researchers report November 6 in Neurology.

Knowing three or more languages did not provide any extra benefit, the authors note.

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor’s degree in journalism from the University of Tennessee, Knoxville, and a master’s degree in science writing from MIT.