What Chomksy doesn't get about child language

I argue that far from enhancing our understanding of language acquisition, Chomsky's ideas have led to stagnation, as linguists have gone through increasingly uncomfortable contortions to relate facts about children’s language to his theories. The problem is that the theories are derived from a consideration of adult language, and take no account of the process of development. There is a fundamental problem with an essential premise about what is learned that has led to years of confusion and sterile theorising.