BEING bilingual exercises the brain and protects against Alzheimer's disease, according to a new study.
Scientists believe mastering two languages acts as a "mental gymnasium" by forcing the brain to multi-task.
There is increasing evidence that bilingual ability improves mental skills and can even stave off dementia.
The study, presented at a US science meeting yesterday, found that bilingual Alzheimer's patients developed symptoms several years later than those who spoke only one language.
The findings contradict popular assumptions that switching between two or more languages has a confusing "Tower of Babel" effect.
Professor Ellen Bialystok, from York University in Toronto, looked at more than 200 Alzheimer's patients, half of whom were bilingual. Among them were immigrants who had regularly used at least two languages since early adulthood. They included speakers of 21 first languages.
The study found that bilingual patients had been diagnosed on average 4.3 years later than those who spoke one language. They also had their first symptoms 5.1 years later than monolingual speakers.