transformational generative grammar

Generative grammar attempts to describe the rules underlying the generation of ever new sentences on the basis of a potentially limited inventory of linguistic material , instead of seeking to analyse large amounts of actually observed language material , the generative grammarian describes rules underlying the generation of infinitely many new utterances based on the competence and the creativity of the native speaker. The approach came to be known as transformational grammar due to the introduction of so called transformations , i.e. rules specifying the transformation of a deep structure into surface structures.