Chomsky, who has taught at the Massachusetts Institute of Technology since 1955, developed a theory of transformational (sometimes called generative or transformational-generative) grammar that revolutionized the scientific study of language. He first set out his abstract analysis of language in his doctoral dissertation (1955) and Syntactic Structures (1957). Instead of starting with minimal sounds, as the structural linguists had done, Chomsky began with the rudimentary or primitive sentence; from this base he developed his argument that innumerable syntactic combinations can be generated by means of a complex series of rules.\x9d\n\x9d\nAccording to transformational grammar, every intelligible sentence conforms not only to grammatical rules peculiar to its particular language, but also to “deep structures,” a universal grammar underlying all languages and corresponding to an innate capacity of the human brain. Chomsky and other linguists who built on his work formulated transformational rules, which transform a sentence with a given grammatical structure (e.g., “John saw Mary”) into a sentence with a different grammatical structure but the same essential meaning (“Mary was seen by John”). Transformational linguistics has been influential in psycholinguistics, particularly in the study of language acquisition by children. In the 1990s Chomsky formulated a “Minimalist Program” in an attempt to simplify the symbolic representations of the language facility.\x9d\n\x9d\nChomsky is a prolific author whose principal linguistic works after Syntactic Structures include Current Issues in Linguistic Theory (1964), The Sound Pattern of English (with Morris Halle, 1968), Language and Mind (1972), Studies on Semantics in Generative Grammar (1972), and Knowledge of Language (1986).