Possibly a linguistic (hah!) confusion. I don't mean that he pioneered the study of language, i.e. linguistics. Clearly people have been studying languages for millennia. When I say he pioneered formal language theory, I mean it in the computer-science sense, that he pioneered the study of formal languages. That's the theory of how to mathematically and computationally parse sequences of tokens into semantic meanings. Chomsky wasn't the first there, since work in symbolic logic (e.g. Frege's work) also considered the formal syntax/semantic mapping. But much modern work in parsing and related areas is derived from Chomsky's work. Any programming-language researcher has heard of and likely used the concept of a "context-free grammar" for example, which Chomsky originated. More information: http://en.wikipedia.org/wiki/Chomsky_hierarchy

Put more simply, I'm saying that he did valuable scientific work in developing his formal analysis of grammars, even if it fails to capture human language. He intended it to capture human grammar, but it's an interesting computation-amenable model of grammar even if it isn't how humans speak, because it is pretty much how we now write programming languages. When computer scientists today talk about "grammars", for example someone saying that they're writing "an ANTLR grammar for Clojure", they mean it in the Chomskian sense.