Transformational generative grammar

In 1957 Noam Chomsky, an American, published Syntactic Structures, a statement of the principles of transformational generative grammar (TG).

This grammar has had a profound effect on the study of all languages, including English. TG was a reaction against structuralism and the first model to acknowledge formally the significance of deep structure.

Transformational generative grammarians set themselves the task of creating an explicit model of what an ideal speaker of the language intuitively knows. Their model must assign a structure, therefore. To all the sentences of the language concerned and only to these sentences.