- Proto-Sino-Tibetan: ?
- Proto-Tibeto-Burman: *d-kʷəy-n (Matisoff, STEDT; Mortensen, 2012); *kwiy=*kwəy ⪤ **d-k-wiy (LaPolla, 1987); *kwiy (Chou, 1972; Weidert, 1987; Benedict, 1972); *kwəy (Chou, 1972; Weidert, 1987)
A widely attested root in Sino-Tibetan languages.
The nasal suffix -n is reconstructed solely on the basis of the Chinese comparandum "犬", where it is said to function as a "collective plural" suffix. This word has almost been completely replaced by 狗 (gǒu, from Old Chinese *Cə.kˁroʔ, "dog") in modern varieties, which Schuessler (2007) considers to be a substrate loanword of Hmong-Mien origin (Proto-Hmong-Mien *qluwˣ (“dog”)), which is in turn perhaps an Austronesian loan, cf. Proto-Austronesian *(u-)(ŋ)kuɣkuɣ (“dog”) (Benedict, 1996). Compare Japanese いぬ (inu, “dog”) (< *iŋku (signature shift), from **i-ŋku[kuɣ] (typical reduction on the right)), and Middle Korean 가히 (gahi, “dog”) (Modern 개 (gae)).
- Old Chinese: 犬 /*kʰʷeːnʔ/ (ZS), /*kʷʰˁenʔ/ (B-S) ("dog")
- Written Tibetan: ཁྱི (khyi, “dog”)
- /*thwiᴮ/ (Luangthongkum, 2013)
- Sgaw: ထွံၣ် (thwì, “dog”)