Chomsky

Chomsky's theories represented, and still represent, both a strong break with American structural linguistics, at the same time, a basic continuity with ideas traceable back to de Saussure and beyond. Chomsky retained the structuralist notion of language as an internally defined system, as well as the basic phrase-structure approach to syntactic analyses and the categorization of language units in traditional parts-of-speech units. In his book Syntactic structures (1957), Chomsky first outlined his theory, which he later solidified in Aspects of the theory of syntax (1965). In this second work, which became known as the "standard theory", Chomsky first devoted considerable time to the notions of competence and performance, arguing that the appropiate goal of linguistic research lies in explaining linguistic competence. Chomsky quickly recognized the limitations of early semantic-based approaches, and from the late 1960´s to the late 1970s, he argued for a theory of grammar that was first known as the "extended standard theory", and later as the "revised extended standard theory". In 1979 Chomsky departed from the revised extended standard theory in a series of lectures known as the Pisa lectures. The general theory to emerge became known as "government-and-binding" (GB) theory and was first presented in book form in Lectures on government and binding  (1981). Chomsky retained the notion of deep structure and transformations, though the set of transformational rules was reduced to one generally applicable rule named "move alpha".

The major difference from previous versions of Chomsky's theory lies in the superposition of a set general systems of principles that operate at deep-and surface-structure levels to determine the grammaticality of every sentence generated by the system. Chomsky outlines seven such systems of principles: government theory, binding theory, bounding theory, theta theory, case theory, control theory, and X-bar theory.