The Word /bon/ in Thai: The Development of its Word Classes The Development of its Word Classes

Abstract

This paper aims at studying the development of the word classes of /bon/ in Thai from Sukhothai period (1238-1438 A.D.) to the reign of King Rama IX of Rattanakosin period (1946-2016 A.D.). The data were collected from published documents and electronic database. There were totally 2,441 tokens of the word /bon/ in Thai. The study reveals that the word /bon/ can be categorized into three word classes, i.e. a noun, an adjective, and a preposition. First, it has been found as a single lexical noun in front of a verb or a verb phrase, behind a verb or a verb phrase, behind a preposition, and at the beginning of a noun phrase from Sukhothai period (1238-1438 A.D.) to the reign of King Rama IX of Rattanakosin Period (1946-2016 A.D.). In this regard, it denotes a spatial orientation that is upper or above a reference level. Second, the adjective /bon/ occurs behind a noun or a noun phrase and conveys the space that is upper or above a reference level, hence linguistically realized into a single noun phrase. This word class has been found from Sukhothai period (1238-1438 A.D.) to the reign of King Rama IX of Rattanakosin period (1946-2016 A.D.). Last, the preposition /bon/ can occur between a verb or a verb phrase and a noun or a noun phrase, or it can occur between a noun or a noun phrase and a noun or a noun phrase. It refers to a position of an entity in relation to another. It has been found from Ayutthaya and Thonburi period (1350-1782 A.D.) to the reign of King Rama IX of Rattanakosin Period (1946-2016 A.D.). It is worth pointing out that the findings imply polyfunctionality and grammaticalization of the word /bon/ in Thai. Also, the preposition /bon/ as a function word is developed from the noun /bon/ or the adjective /bon/ which are the content words. The gradual change of the word /bon/ coincides with the universal phenomenon of grammaticalization.