Northern Khmer, the dialect spoken in parts of northeast Thailand, has been isolated from mainstream Khmer for nearly six centuries.
Experts say it appears to have diverged from the form spoken in Cambodia today at the end of the Angkor Kingdom in the mid-1400s when Khmers in the region came under the control of the ascendant Thai kingdom.
Northern Khmer wasn’t affected by changes to Khmer in Cambodia in large part because northeast Thailand and Cambodia are divided by the Dangrek escarpment. More than any other dialect, it has remained similar to the Khmer spoken during the Angkor Empire.
Khmer identity began weakening in Thailand from the turn of the 19th century as the Thai government initiated a nationalistic program, including compulsory use of Thai in schools, to rein in its ethnic groups.
Events abroad also stigmatized Khmer identity, according to Peter Vail, a professor of Anthropology at Georgetown University in the US. “With Thailand and Cambodia on opposite ideological ends in the Cold War, Khmer identity was publicly stigmatized, denigrated, and even regarded in some cases as potentially subversive,” wrote Vail in a 2006 article published in The International Journal of the Sociology of Language.
A Thai uproar starting in the late 1950s over possession of Preah Vihear, an ancient Khmer temple on the border, stirred a wave of xenophobia against Cambodia, in which Thai authorities prohibited the use of Khmer in public functions and, in some cases, ordered Khmer language materials to be burned, according to Vail.
A further blow came during the 1970s as Cambodia spiraled into chaos and war, further tainting Thai attitudes toward Khmers. Many Khmers in Thailand became embarrassed about their ancestry and would often hide that they could speak Khmer, Vail says.
Khmers in Surin were drawn deeper into the Thai identity during the 1970s and ‘80s by massive infrastructural developments that changed their rural lives.
Faster and cheaper transportation improved villagers’ access to the cities. Rural electrification and the rise of Thai mass media that followed it brought urban life to the village.
“Many villagers, although still living rural lives, imagine themselves partaking in urban, cosmopolitan life. Speaking Thai (and other languages, including English) is part of this national imagining; speaking Khmer is not,” wrote Vail, warning that Northern Khmer may declining faster than previously expected.