The linguistic phenomenon of polyfunctionality, in which a from can perform more than one syntactic function and can denote different yet related meanings, is of particular interest from the linguistic typological, historical linguistic..., and cognitive linguistic points of view. This study primarily focuses on the form /tôŋ/ in Thai, which constitutes an interesting instance of polyfunctionality as its counterparts are found to be prevalent in the Southeast Asian languages. However

The study aims to investigate word classes, functions and contexts of the word /bon/ in Thai, along with its meanings and concepts as well as processes and mechanisms of semantic change and development from Sukhothai period to the reign of King Rama... IX of Rattanakosin period (2016 A.D.), using cognitive semantics, grammaticalization, and lexicalization as conceptual frameworks. There were 2,441 tokens of the word /bon/ in total, according to this study. It was found that, firstly, the word /bon