Proto-Hmong–Mien language
Ratliff (2021) estimates that the split between Hmongic and Mienic had occurred before 2500 BP, since the Old Chinese words 鐵 tiě ‘iron’ and 下 xià ‘descend’ were both borrowed separately by Proto-Hmongic and Proto-Mienic.[1] In earlier studies, the date of proto-Hmong-Mien has been estimated to be about 2500 BP by Sagart, Blench, and Sanchez-Mazas (2004),[2] as well as by Ratliff (2021:247).[12] Even though Mienic languages usually have vowel length, Ratliff ascribes this to areal features that were borrowed after the breakup of Proto-Mienic.[25] Proto-Hmong–Mien shares many lexical similarities with neighboring language families, including Austroasiatic, Kra-Dai (Tai-Kadai), Austronesian, and Tibeto-Burman (Ratliff 2010).Many lexical resemblances are found between the Hmong-Mien and Austroasiatic language families (Ratliff 2010), some of which had earlier been proposed by Haudricourt (1951).[33] Many lexical resemblances are found between the Hmong-Mien and Kra-Dai language families, although the tones often do not correspond (Ratliff 2010).Many lexical resemblances are found between the Hmong-Mien and Austronesian language families, some of which are also shared with Kra-Dai and Austroasiatic (Ratliff 2010).Guillaume Jacques (2021) notes that there are Tibeto-Burman parallels for various Hmong-Mien words that are found specifically in rGyalrongic and neighboring Qiangic languages.