Abstract: The Tang and Song Dynasties were in an important period in the history of Chinese language development. The vernacular
trend of literary language attracted peoples attention, which is manifested in the maturity of vernacular novels, the formation of
vernacular poetry schools, and the colloquialization of poetry language. The reasons are multi-faceted, but the tentacles of the
commodity economy penetrated into the field of literature, and the need of the masses brought about by the commercialization of
literature was undoubtedly the most powerful driving force for the vernacular trend of literary language.

Key words: Tang?and?Song?literature, ?commercialization, ?language, ?vernacular?trend