Jaratjarungkiat, S., Park, K.-E., Pichetpan, N. and Tan, S. Y. H. (2023) “The Grammaticalization of the Copulas /pēn/ and /kʰɯ̄ ː/ in Thai”, Journal of Mekong Societies, 19(2), pp. 92–119. available at: https://so03.tci-thaijo.org/index.php/mekongjournal/article/view/266198 (accessed: 2 September 2026).