via the Cornell Southeast Asia Program: Readers may be interested in this talk by Pittayawat Pittayaporn on 12 February 2021. Registration details in the link.
The linguistic landscape of central Thailand prior to the 13th century was radically different from today. It is generally believed that the area was pre-dominantly Mon-Khmer speaking. O’Connor (1995) suggests that the Tai migration into Southeast Asia started in the first millennium A.D. Diller (2000) similarly suggests that the southwest-ward migration of Tai speakers started in the 10th century. In this talk, I discuss when and how Old Thai, the language attested in 14th-15th century inscriptions, came to replace aboriginal languages of the area. By examining its development from Proto-Southwestern Tai (Pittayaporn 2009), I argue that Old Thai was first spoken in central Thailand some time before the oldest surviving Thai text was inscribed, perhaps in the 13th century. In addition, I hypothesize based on linguistic and genetic evidence that the Thai language came to dominate central Thailand mainly through migration of Tai-speaking population, rather than ethnolinguistic assimilation of indigenous non-Tai speakers.
Source: Gatty Lecture: Old Thai and the Arrival of Thai in Central Thailand | Facebook