According to a York University study.
Half of the volunteers came from Canada and spoke only English. The other half came from India and were fluent in both English and Tamil. The volunteers had similar backgrounds in the sense that they were all educated to degree level and were all middle class. The researchers found that the people who were fluent in English and Tamil responded faster than those who were fluent in just English. This applied to all age groups. The researchers also found that the bilingual volunteers were much less likely to suffer from the mental decline associated with old age.
I hope the same benefits apply to those like myself who are only semi-fluent in my second language /
J’espere que les memes benefices sont applicable aux personnes comme moi que ne sont que demi-courant dans le deuxieme langue!