Why is the worldwide number of Hmong-Mien speakers difficult to estimate?

Estimating the worldwide number of Hmong-Mien speakers is difficult primarily because of the discrepancy between ethnic classification and linguistic reality.

Most speakers belong to the Miao and Yao nationalities in China, where the government reports population figures based on these ethnic groups rather than language use. These categories are based on culture, politics, and self-identification rather than purely linguistic criteria. Consequently, these groups include individuals who speak languages outside the Hmong-Mien family, while others who speak Hmong-Mien languages may be classified under different nationalities.12

Because approximately six out of every seven speakers reside in China, these official census figures significantly influence global estimates. Due to this overlap of ethnic and linguistic categories, the actual number of Hmong-Mien speakers may be lower than the estimated 10 million.1