The aim of the paper is to trace the development of the grammatical structure of the vernacular (colloquial) Chinese language through the changes which took place in the grammatical system (specifically in the system of function words) during the 3rd-14th centuries. In other words, I intend to closely follow the entire process of the changes from the moment the function element originated up to its status (or disappearance) in the modern language. To fulfill the task a thorough examination of an extensive body of source-material was undertaken. A precise selection of the source-material was the first step towards a successful response to the proposed project. With regard to the paper under consideration the following source-materials were carefully examined: the early Chinese translations of the Buddhist works (as the main source) for the Liuchao epoch, the Chan-Buddhist yulu for the Tang, the texts in the ss genre and San Chao bei meng hui bian for the Song-Yuan period. The essay consists of three parts: the grammar of the 3rd-5th cc A.D., or Liuchao period, Chinese grammar of the Tang Dynasty, and the changes undergone during the Song-Yuan epoch.