Here’s another reason being bilingual is a good thing. It can delay the onset of Alzheimer’s disease and its symptoms for between years. This is the surprise finding from researchers at Toronto's Rotman Research Institute at Baycrest.

In a study of more than 100 bilingual patients and 100 monolingual patients, they found that the bilinguals experienced the onset of symptoms and were diagnosed with Alzheimer’s disease between four and five years later than monolingual patients.

This confirms results from an earlier study.

What is not clear is why. It may have something to do with a unique ability in people who speak more than one language. Research has shown they have an ability to suppress irrelevant or interfering information so they can concentrate on information that is relevant.

In other words, they damp down the language they are not using and focus on the language they are using.

One of the researchers finds that bilingualism does not necessarily stop the brain from degenerating, but rather it may provide something that compensates for the brain degeneration.

And there is some evidence that speaking more than two languages provides even more of a benefit.