This thesis is an endeavour to pursue a study of the usage of Thai Prose during the Ayudhya period which begins in the reign of King Uthong and ends in the reign of King Rama III. The thesis comprises eight chapters: chapter one states the problems, chap¬ter two discusses the division of the Thai language into periods, chapter three to chapter seven deal with the usuage of Ayudhya prose, the last chapter contains the summary of the thesis and recommendations. The chapters concerning the usage of language discusses three main topics, the words, the idioms and the styles, each of these topics reveals their specific usage in the Ayudhya Prose. In the last chapter, not only the distinctions between the usage of prose during the Ayudhya period and at the present time are summarized, but suggestions for further studies are also given. The data upon which the author bases his essay are all taken from primary sources of about 20 pieces. Most of them are official letters, memoranda, chronicles, inscriptions and laws. Besides the analysis of the, usage of prose during the Ayudhya period, the author also compares it with the modern usage of the language. It is expected that the thesis would contribute to the knowledge of the Thai language in its historical aspects which will be greatly useful in comparative studies of the language, and it could be used as a model for the study of the changes in the Thai language. It is hoped that the thesis will play an im¬portant role in the progress of the study of the Thai language.
