Origins of Transformational Generative Grammar

2.1. Corpus Analysis

For American structuralists, an empirical science studies only observable phenomena. For descriptive purposes, a language was defined in terms of a corpus. A linguistic corpus has a level of phonological structure, a level of morphological structure and a level of syntactic structure. They believed that when all elements of the corpus were grouped and labelled at each level, the grammar of the language was complete.

Structural grammars offer an inventory of forms and constructions which appear in a limited  corpus; they do not provide the rules needed to construct an endless range of possible grammatical sentences. For Chomsky, a corpus can never represent the whole language, but will only cover an incomplete and a selective sample of it because language is infinite and creative in nature. TGG supporters suggest that instead of describing a corpus, a linguist can arrive at an inclusive grammar of language by describing its underlying system of rules, which is not contained within the corpus, but lies beyond it, in the minds of the speakers. The study of this system is more important than the study of the actual sentences.