Thanks, all, for some fascinating links. Yes, Werner, I completely share your reservations about the positive and negative inferences one can legitimately draw from this kind of evidence. An outstanding feature of speech, for me, is the way the body utilises components that clearly had another primary function initially. This tends to lead me towards those who argue that language is borne of deep-seated pattern formation in the brain - that it is only one output of a deeper function. I shall tote off Schoenemann's article to read tonight!