[C]hildren learning to speak just don’t have enough information to form the complex grammatical maneuvers that allow them to generate unlimited new and original sentences, yet they do so with ease… Chomsky’s hypothesis was that there are inborn structures in our brain, what he called a language acquisition device, or a LAD, which gives us a natural propensity to organize the spoken language that we hear in various grammatical ways. Without that, we couldn’t get started as language learners. If he’s right, language structure is hardwired as a kind of universal grammar.
What makes me human?: Noam Chomsky on language acquisition | BBC Radio 4