Ethnic minorities can understand Sihanouk's speech, probably because they belong to the Khmer family with Cambodians.

The Khmer people left Yunnan for the south not very early, but probably from the end of the Warring States Period to the period of Qin reunification, which was mainly oppressed by the Central Plains civilization and the powerful ethnic groups in Yunnan-Guizhou Plateau.

There were many such chain reactions in ancient times. The Khmer people went south to establish the Zhenla and Khmer empires, and later destroyed the powerful alliance regime established by the authentic Mongols in Lower Myanmar and western Thailand. ~~~~~~~