Citing the fact that both the Zhuang and Thai peoples have the same exonym for the Vietnamese, "kɛɛu", Jerold A. Edmondson of the University of Texas at Arlington posited that the split between Zhuang (a Central Tai language) and the Southwestern Tai languages happened no earlier than the founding of Jiaozhi in Vietnam in 112 BCE but no later than the 5th-6th century AD.