Why are Mun speakers on Hainan classified as Miao despite speaking a Mienic language?

In China, the classification of ethnic groups is not based solely on linguistic criteria; it also incorporates factors such as culture, politics, and self-identification.1

While the Hmong-Mien languages are divided into the Hmongic (Miao) and Mienic (Yao) subfamilies, the official "nationality" designations used by the Chinese government do not always align with these linguistic branches. For cultural reasons, speakers of the Mun language on Hainan Island are classified as members of the Miao nationality, despite the fact that their language is linguistically Mienic. This reflects the broader reality that these designations represent the concept of "nationality" rather than a strictly linguistic classification.12