An overview of Noam Chomsky's theories about transformational grammar and phonology is given. Since Chomsky was interested in characterizing what it is to know a language, the ways in which we demonstrate knowledge of our native language are discussed in detail. Particular emphasis is placed on describing how the transformational approach actually works. The differences between transformational theory and structural linguistics are also pointed out. In the second part of the present work, there is a brief discussion of the transformational grammarian's theory of psycholinguistics, called cognitive psycholinguistics. The discussion focuses on a comparison of cognitive psycholinguistics and classical behaviorist learning theory. (PMP)