Why are first-graders smarter than Chomsky?

Linguistics, it turns out, is very difficult. Although it’s been over half a century since Chomsky sparked the charge to develop complete, generative grammars for languages (a set of rules that explain how to build grammatical sentences), success has been less than complete — this despite the fact that children learn languages with ease. Why is it so difficult for a group of the world’s most brilliant academics?

Here’s a good explanation from Ray Jackendoff, in Foundations of Language:

It is useful to put the problem of learning more starkly in terms of what I like to call the Paradox of Language Acquisition: The community of linguists, collaborating over many decades, has so far failed to come up with an adequate description of a speaker’s [knowledge] of his or her native language. Yet every normal child manages to acquire this f-knowledge by the age of ten or so, without reading any linguistics textbooks or going to any conferences. How is it that in some sense every single normal child is smarter than the whole community of linguists?

The answer proposed by the Universal Grammar hypothesis is that the child comes to the task with some [preconceptions] of what language is going to be like, and structures linguistic input according to the dictates (or opportunities!) provided by those expectations. By contrast, linguists, using explicit reasoning–and far more data from the world than the child–have a much larger design space in which they must localize the character of grammar. Hence, their task is harder than the child’s: they constantly come face to face with the real poverty of the stimulus.