Despite the fact that Miao-Yao (or Hmong-Mien) is one of the major language families of East and Southeast Asia, this work is only the second full-length descriptive grammar of any Miao-Yao language published in English. It focuses on Xong, a language belonging to the Miao branch of the family. Xong has approximately 900,000 speakers, the vast majority lives in Hunan and Guizhou Provinces in South-Central China. In particular, this description concentrates on several fully mutually intelligible Xong varieties spoken in Fenghuang County, located in the Hunan Province. In producing this work, the author primarily relies on the fieldwork data he collected over a period of ten months in Fenghuang County. He also made use of many of the previously published Chinese-language descriptions of Xong. The results are of use to scholars with an interest in the Miao-Yao family in particular or in the languages of East and Southeast Asia more in general.