The Science of Language by Noam Chomsky Page A

are no homologous structures for language, there's no comparative work. The only comparative work is on the precursors – like the sensory-motor system.
    And the same is true on the conceptual side. I just don't see how you can – with our current understanding, at least – hope to get any possible insight into the evolution of the elementary concepts with their strange internalist properties. [Again] they're universal – if you go to a New Guinea native, he or she's going to have basically the same concept RIVER that we have. But we have no idea how it got that way.
    JM: There are lots of just-so stories to the effect that it has something to do with evolution in the sense of selection giving advantages .
    NC: But what's advantageous about having a concept RIVER that has the features we seem to be sensitive to that could have no discernible bearing on survival or selection? We can make up thought experiments about RIVER which you couldn't even imagine if you're a New Guinea native. Imagine a small phase change that turns the Charles River into a hard substance, which is apparently possible. And then you paint a line on it, and you start driving trucks on both sides of the line, so it becomes a highway and not a river. You can't explain that to a New Guinea native; none of the other notions you need to entertain the thought of a river undergoing a phase change and becoming a highway are around; so how could selection have played a role in leading us to acquire the features RIVER has that come into play when we engage in thought experiments like these, ones that lead us to declare that a river has become a highway?
    In fact, the native has the same concept; if he or she grows up here or there, he or she's going to have the concept RIVER. So he or she's got it. But how could it possibly be selected? What function does it have in human life, for that matter? And since that's true of every elementary concept – take, say, PaulPietroski's example in his recent paper about France beinghexagonal and a republic. Why should we have that notion of France? It can't have any selectional role . . .
    JM: That seems pretty obvious to me. Let me get back toLaura Petitto just for a moment and what she had to suggest about the way in which the STG (Superior Temporal Gyrus) looks for certain kinds of patterns. Her idea was that, at least in part, the reason we are bimodal – that we could develop without difficulty in either or both of two ways – was because you're using the same system in both cases .
    NC: I suspect that there are other domains in which it could happen. Maybe you could do it in dance. I don't know, but I presume that infants would be capable of externalizing their language in dance motions – with their legs, let's say. Or perhaps any movements of your head, or eye blinking . . . In fact, people with severe paralysis.
    JM: But if they did it with dance, say, they'd still require the visual system and certain kinds of patterns . . .
    NC: We can't do it with smell, because we're not developed enough; we can't use taste, because we don't have the sensory range – maybe dogs could, but we can't. So you're stuck with vision andhearing. Those are the only adequate sensory capacities that we have. So everything is going to use vision and hearing, and some kind of action that we can carry out with our bodies. That's just given. OK, that leaves certain possibilities. But perhaps any possibility that makes use of those capacities will work for externalization. And she could be right; it's all going to have to fall into certain subcategories, because that's all that our brains can process. So whenever externalization comes along, as an aspect of language, it's going to have to make use of these facts about our nature. If dogs suddenly underwent a mutation in which they got Merge, maybe they'd use the sense of smell.
    JM: Another fascinating aspect of her work is that she suggests thatrhesus, macaques, and several other