 The elderly Sui people of Hồng Quang claim that 8 Sui families had migrated to Vietnam from China 100 to 200 years ago, 2 of which have now already assimilated into other ethnic groups.Edmondson & Gregerson (2001) have found that the Sui dialect of Hồng Quang is most similar to the Sandong 三洞 dialect of Sui as spoken in Shǔilóng 水龙, Sandu Shui Autonomous County, Guizhou, China.Sui has seven vowels, .