Why do many linguists treat Hmong-Mien as an independent language family?

Many linguists classify Hmong-Mien as an independent language family because evidence for alternative genetic relationships remains inconclusive. While some scholars have proposed links to Sino-Tibetan, Austroasiatic, or Austronesian groups, these theories have not gained general acceptance.1

The primary reasons for this independent classification include:

• Lack of Genetic Evidence: Standard linguistic methodology relies on recurrent sound correspondences in basic vocabulary to establish genetic affiliation. Current research does not support a genetic link between Hmong-Mien and other proposed families.1
• Distinguishing Borrowings from Native Vocabulary: Hmong-Mien languages contain a high number of Chinese loanwords. Linguists attribute observed similarities in grammar, phonology, and word structure to this extensive historical contact and widespread bilingualism rather than a shared ancestry.1
• Need for Further Research: Until scholars can definitively separate these layers of Chinese borrowings from the native Hmong-Mien vocabulary, wider family connections cannot be resolved. Consequently, treating the group as an independent family is considered the most prudent scientific position.1