Research on the Grammaticalization of Chinese NaoDao

Grammaticalization is not just progressive diachronic changes in the internal language,but there may be grammaticalization stages with different characteristics in the same synchronic state.Start with the two aspects of the diachronic and synchronic,"nandao" as the object;grammaticalization,the theoretical basis.To observe and analyze the different usages of the synchronic level,inquiry the evolution process of the diachronic level.And summarize the grammaticalization path and motivations and mechanisms of "nandao".The development and evolution of "nandao" is from verbal polarization phrase to speculation tone of adverb to rhetorical tone of adverb.