This course is designed to enable learners to study the development of the Thai language from past to present. This course covers the characteristics and outcome of Thai alphabets in the Sukhothai, Ayutthaya and Rattanakosin periods. Including the change of Thai characters from the past to the present until getting a foreign language into the Thai language. To analyze and compare the development of the Thai language. A deeper understanding of the language and applying knowledge to teach the Thai language effectively.