TG involves the use of defined operations called transformations to produce new sentences from existing ones. Noam Chomsky’s 1965 book Aspects of the Theory of Syntax developed the idea that each sentence in a language transformational generative grammar pdf two levels of representation — a deep structure and a surface structure. Chomsky believed there are considerable similarities between languages’ deep structures and that these reveal properties, common to all languages, that surface structures conceal. Similarly, deep structure was devised largely for technical reasons relating to early semantic theory.
Although it was well understood that linguistic processes are in some sense “creative,” the technical devices for expressing a system of recursive processes were simply not available until much more recently. I finally met this talkshow host” and “You always detested this talkshow host”. Chomsky developed a formal theory of grammar where transformations manipulated not just the surface strings, but the parse tree associated with them, making transformational grammar a system of tree automata. For more details see the Transformations section below.
Though transformations continue to be important in Chomsky’s current theories, he has now abandoned the original notion of Deep Structure and Surface Structure. 1990s Chomsky sketched out a new program of research known as Minimalism, in which Deep Structure and Surface Structure no longer featured and PF and LF remained as the only levels of representation. To complicate the understanding of the development of Noam Chomsky’s theories, the precise meanings of Deep Structure and Surface Structure have changed over time — by the 1970s, the two were normally referred to simply as D-Structure and S-Structure by Chomskyan linguists.
Terms such as “transformation” can give the impression that theories of transformational generative grammar are intended as a model for the processes through which the human mind constructs and understands sentences. Chomsky is clear that this is not in fact the case: a generative grammar models only the knowledge that underlies the human ability to speak and understand. Perhaps more significantly, he made concrete and technically sophisticated proposals about the structure of language, and made important proposals regarding how the success of grammatical theories should be evaluated. In the 1960s, Chomsky introduced two central ideas relevant to the construction and evaluation of grammatical theories.
The first was the distinction between competence and performance. The second idea related directly to the evaluation of theories of grammar.