The Proto-Hmong–Mien language is the reconstructed ancestor of the Hmong–Mien languages. The time of proto-Hmong-Mien has been estimated to be about 2500 BP by Sagart, Blench, and Sanchez-Mazas and about 4243 BP by the Automated Similarity Judgment Program (ASJP). Lower-level reconstructions include Proto-Hmongic and Proto-Mienic.
Past reconstructions include Wang & Mao (1995).
Ratliff (2010) used 11 criterion languages for her reconstruction.
Wang & Mao (1995) base their Proto-Hmong-Mien reconstruction from the following 23 criterion Hmong-Mien languages.
Martha Ratliff's 2010 reconstruction contains the following phonemic inventory.
Medial consonants are *-j-, *-l-, and *-r-.
Proto-Hmong–Mien had the following syllable structure (Ratliff 2010:10):
(C) C [j/w/l] [i̯/u̯] (V) V C (C)T
Ratliff does not reconstruct vowel length for either Proto-Mienic or Proto-Hmong-Mien. Even though Mienic languages usually have vowel length, Ratliff ascribes this to areal features that were borrowed after the breakup of Proto-Mienic. Neighboring languages with vowel length include Cantonese and Zhuang.
Below are some reconstructed words roughly belonging to the semantic domains of agriculture and subsistence (Ratliff 2004; Greenhill et al. 2008; Starling 1998). Terms for domesticated animals and non-rice crops are usually shared with Chinese, while vocabulary relating hunting, rice crops, and local plants and animals are usually not shared with Chinese.