I have just come across an article in the NewScientist of 5 May : while there is nothing really new in it for the experienced language enthusiast, it does present the findings of old and recent research into bilingualism and second language learning in an interesing, well-written way.
I very much agree with the author, Catherine de Lange, when she says
“speaking a second language can change everything from problem-solvifng skills to personality. It is almost as if you are two people.”
She also mentions the benefits of learning languages in later life (hear, hear!!!) and the benefits attached to making the initial effort.