From objective to subjective and to intersubjective functions: The case of the Thai ‘truth’-lexeme

Borrowed lexemes developing into discourse markers (DMs) are uniquely valuable research topics from contact linguistic and grammaticalization perspectives. Although a large number of Sino-Thai lexemes are commonly used, there has not been any serious attempt to analyze such lexemes. The aim of this study is to describe diverse discourse functions of the Sino-Thai lexemes involving ciŋ ‘true’ drawing upon corpus data, to analyze their development with respect to grammaticalization mechanisms, to identify their DM properties, to compare with the developments reported in other languages, and to construct a conceptual-functional network. The data obtained from diverse sources, including historical and contemporary dictionaries, online resources, reference grammars, contemporary corpora, among others show that the lexeme ciŋ ‘true’ denotes ‘true, truth, real’ (objective meaning) as a lexical word, but it also functions adverbially as an intensifier marking ‘surely, definitely’ (subjective meaning) which is a natural development of its lexical meaning. In the domain of discourse, the lexeme acquired a number of interactional functions (intersubjective meaning). A review of the Thai DMs based on ciŋ ‘true’ (truth-DMs) in light of grammaticalization parameters shows that changes characterizable as desemanticization, extension, and decategorialization are observable, whereas erosion is either not observed or its reverse is often found. Despite variable degrees of semantic bleaching, the semantic change in the movement from objective to subjective, and further to intersubjective meanings, is prominent. The functional similarity between truth-DMs across languages notwithstanding, the differences are much greater. These findings contribute to the understanding of the role of source semantics as well as its limits in the developmental paths of DMs.