In linguistics, a transformational grammar or transformational-generative grammar (TGG) is a generative grammar, especially of a natural language, that has been developed in the syntactic structures of phrase structure grammars (as opposed to dependency grammars). Transformational grammar is the tradition of specific transformational grammars. Much current research in transformational grammar is inspired by Chomsky’s Minimalist Program.
In 1957, Noam Chomsky published Syntactic Structures, in which he developed the idea that each sentence in a language has two levels of representation — a deep structure and a surface structure. The deep structure represented the core semantic relations of a sentence, and was mapped on to the surface structure (which followed the phonological form of the sentence very closely) via transformations. Chomsky believed there are considerable similarities between languages’ deep structures, and that these structures reveal properties, common to all languages that surface structures conceal.