Jaratjarungkiat S, Park K-E, Pichetpan N, Tan SYH. The Grammaticalization of the Copulas /pēn/ and /kʰɯ̄ ː/ in Thai. JMS [internet]. 2023 Aug. 31 [cited 2026 Sep. 2];19(2):92-119. available from: https://so03.tci-thaijo.org/index.php/mekongjournal/article/view/266198