> One speculation is that language can *develop* in
> variety of types of social create, possibly as play among the young,
> or as jump in complexity of the kind of signals birds and chimps use
> for differing purposes.
Just a fottnote. The following was passed on to me by a physicist friend, who said that had he seen it when he was in the fifth grade he would have become a biologist rather than a physicist. I call it to your attention because you use the word "develop," and Lewontin has some very caustic remarks on how misleading that metaphor is.
http://www.youtube.com/watch?v=we4ZzjKxFHM
Carrol
P.S. I agree with most of what you say in this post.