Knowing how to speak more than one language in Canada is always a good thing. Not only is it helpful to be able to speak both of our country's two official languages, it can also be handy to know your way around one of the dozens of other "unofficial" languages spoken here.

Now add to those benefits a finding from new Canadian research that speaking multiple languages might help protect your cognitive health in older age.

In research presented this week at the annual meeting of the American Association for the Advancement of Science in Washington, DC., researchers from York University in Toronto revealed that knowing two languages -- and speaking them regularly -- can delay the onset of dementia, compared to people who spoke only one language.

The study, co-authored by York psychologist Ellen Bialystok, looked at 211 people with probable Alzheimer's disease; 102 were bilingual and 109 monolingual. The reserachers then noted the age at which the patients' cognitive impairment had started.

The results, which appear in Neurology, showed that bilingual patients had been diagnosed 4.3 years later, on average than those who spoke only one language.

As well, they reported onset of symptoms 5.1 years later than monolingual patients.

The findings the same regardless of the gender of the patients, their education level or their occupational status.

"One of the reasons bilingualism has these powerful mechanisms including protecting against early symptoms of dementia is because it's one way to keep your brain active," Bialystok told reporters at the meeting.

"Every little bit helps. The longer you've been bilingual, the more you use all your languages, the more fluent you are, all of those things contribute.

"Even if you're starting to learn a language at 40, 50, or 60, you're unlikely to become bilingual, but you are keeping your brain active. So you're contributing to cognitive reserve through very engaging and intense activity," she said.