Noam Chomsky (born 1928) is an American linguist, known (among other things) for his controversial views on language acquisition. According to Chomsky, humans possess a “language acquisition device” (LAD), an innate ability to construct and understand syntactical structures of language. When Chomsky’s theory was presented, it caused a profound change in the area of psycholinguistics, challenging the traditional and behaviourist explanations of language acquisition, which were based on learning theory.