Human language appears to be unique in the animal kingdom, but precisely what its role is in distinctively human thought has been the subject of intense debate. For many, this issue is sidelined in favor of investigating the perhaps more obvious role of language in distinctively human communication. The net result appears to be that while philosophers and psychologists have offered quite explicit proposals about the relationship between language-and-thought or language-and-communication, rarely are the two lines of inquiry integrated. The linguist Noam Chomsky has offered a quite explicit proposal about the nature of language itself, paired with suggestions on its relationship to thought (while remaining rather vague) and communication (while remaining rather dismissive). On his view, "core" language is its mechanism for recursive hierarchical structure building (syntax), and its interfaces. In this talk, I assume that Chomsky's view is basically correct, but consider how to situate it within more mainstream cognitive science. In particular, if language is "for" thought, in virtue of what does it give us the ability to think thoughts that are beyond the capacity of non-human animals (Spelke)? And if it was only later co-opted "for" communication, how did that happen (Tomasello/Bloom)? I show how an integrative picture is possible so long as we assign a critical role to another "core" aspect of language, the ability to form lexical concepts (Pietroski). This proposal allows us to explain some otherwise puzzling phenomenological data, as well as the basic fact that while high school kids have learned on the order of ~60,000 lexemes with little to no explicit instruction, "herculean efforts" to teach novel words to our ape cousins results in acquisition of at best ~300 symbols