Innate. Though I hope you'll list some things from the book; perhaps he has arguments for both? Technically, of course, it IS both: an infant of English-speaking parents isn't going to start talking in French! But the desire to communicate is innate: we are social animals. Once our brains develop sufficiently to discern and wonder about the world around us (usually by about 6 months), we demand interaction. (Prior to about 5 months old, even after good vision develops, infants are only truly "aware" of themselves, and that only in a rather amorphous way. They cry, yes, but in the earliest weeks are not capable of differentiating between, say, hunger and being too cold; all they "know" is that they're miserable in some way.) If somehow a group of 6-months-olds could be left completely on their own, I would predict that by 12 months at least some meaningful sounds would have developed and that by 18 months they would have a rudimentary vocal language of some kind. At least the equivalents of I'm hungry, I'm hurt, check this out, and hey, that's mine!
