There's a really interesting article from the NYT about the cognitive benefits of bilingualism. I've believed this at some weird intuitive level since I was a teenager, and I made this weird half-hearted vow to spend my life learning languages. I haven't actually done very well. I've learned tiny bits of a lot of languages – but althought I've studied at some academic level about 20 languages, for most I've only done a semester or even less. I've only reached actual fluency in one other language (Spanish). Then, in descending order, I might list French, Korean, Russian, Portuguese, Japanese… where I have some rudimentary survival ability. My desire for and interest in languages is obviously much stronger than my mental capacity and/or my actual deep-seated motivation to learn them. I nevertheless believe one of the greatest and most lasting gifts we can give children is 'another language.'