Speaking two languages may delay dementia
A study in the US journal Neurology is the first of its kind to show that the protective effects of bilingualism can extend to people who are illiterate.
The researchers looked at a population of 648 people in India with an average age of 66. All had been diagnosed with some form of dementia.
When analysing the data, they found that those who spoke two languages developed dementia about 4.5 years later than those who spoke just one language.
The differences persisted whether they were able to read or not. Fourteen per cent of those in the study were illiterate.
The later onset of memory loss, including Alzheimer's disease and vascular dementia, was also seen regardless of factors such as education, gender, occupation and rural or city residency.
"Our study is the first to report an advantage of speaking two languages in people who are unable to read," said study author Suvarna Alladi, with Nizam's Institute of Medical Sciences