From Proto-Vietic *-ŋiː, from Proto-Mon-Khmer *t₂ŋiiʔ (“day, sun”); cognate with Vietnamese ngày, Khmer ថ្ងៃ (thngay, “day”), Koho töngai (“day”), Pacoh ingay (“day”), Khasi sngi (“day”), Mon တ္ၚဲ (“sun, day”).
From Proto-Vietic *-ŋiː, from Proto-Mon-Khmer *t₂ŋiiʔ (“day, sun”); cognate with Muong ngày, Khmer ថ្ងៃ (thngay, “day”), Koho töngai (“day”), Pacoh ingay (“day”), Khasi sngi (“day”), Mon တ္ၚဲ (“sun, day”).
The Vietnamese words for "day" and "night" and their cognates have the same distribution within Vietic: reflexes of *-ŋiː (“day”) and *teːm (“night”) are only attested in Thổ, Pong and Viet-Muong, i.e. the "innovative Vietic" group, lacking cognates in the generally more conservative languages. In the case of "day", the upper register tone in Thổ Cuối Chăm ŋaj¹ (A1) shows that there probably was a presyllable with voiceless initial (if the presyllable was voiced or if this was a monosyllabic word with nasal onset, the expected tone would be A2). This presyllable corresponds to the *t- in other Austroasiatic languages (or some other sound in Northern Austroasiatic in this case, see đêm (“night”) for examples). The tone of the Vietnamese word is huyền (A2), showing that the presyllable was already lost by the Common Viet-Muong stage, before tones started to develop. The presyllable, although can not be explicitly identified as *t- by Vietic evidences alone, is represented by the dash *-. Therefore, the relationship between Proto-Vietic *-ŋiː and other Austroasiatic words is unquestionable.
- (Hà Nội) IPA(key): [ŋaj˨˩]
- (Huế) IPA(key): [ŋaj˦˩]
- (Hồ Chí Minh City) IPA(key): [ŋa(ː)j˨˩]
Audio (Hồ Chí Minh City) (file)