- Proto-Sino-Tibetan: *b-kɑ-n (Coblin, 1986)
- Proto-Tibeto-Burman: *b-ka-(n/m/ŋ) (Matisoff, STEDT); *b-ka-n (Matisoff, 2003; Mortensen, 2012); *ka (Benedict, 1972; Weidert, 1987; LaPolla, 1987); *ka (*B) (Coblin, 1986); *kɑ (Chou, 1972)
Derivative:Proto-Sino-Tibetan*kak(“difficult, hard”).
CompareProto-Tai*Ĉ.qɤmᴬ(“bitter”) (Thaiขม(kǒm),Laoຂົມ(khom)); also compare:Thaiขื่น(kʉ̀ʉn),Laoຂື່ນ(khư̄n,“bitter, astringent, ascerbic”).
*kaʔ
- bitter
- Old Chinese:苦/*kʰˤaʔ/ (B-S),/*kʰaːʔ/ (ZS) ("bitter; a bitter plant");/*kʰˤa-s/ (B-S,unlisted),/*kʰaːs/ (ZS) ("difficult, hardship")
- Middle Chinese:苦(kʰuoX, kʰuoH/)
→Japanese: 苦 (く, ku)
Korean: 고 (苦,go)
Vietnamese: khổ(苦)
→Vietnamese: khó(“hard, difficult; delicate”)
- Bodish
- Tibetic
- Tibetan:ཁ་བ(kha ba,“bitter”)
- Proto-Kuki-Chin:*khaa
- Naic
- Proto-Naish:*kʰa
- Naxi:ka(/kʰɑ³³/)
- Narua:kha(/qʰɑ˥/)
- Laze:[Term?](/kʰɑ˧/)
- Nungish:
- Rawang:ka(“bitter”)
- Trung/Drung/Dulong:ka(“bitter”)
- Proto-Bodo-Garo:*kha²
- Lolo-Burmese
- Burmish
- Achang:khoh
- Burmese:ခါး(hka:,“bitter”)
- Loloish
- Northern Loloish
- Yi (Liangshan):ꈌ(ke,“bitter”)
- Katso:ka³³
- Central Loloish
- Lisu (Northern):ꓘꓪꓽ(kʰwɑ̀,“bitter, too salty”)
- Lolopo:kar(“bitter”)
- Southeastern Loloish
- Proto-Karen:*khaᴮ (Luangthongkum, 2013)
- S'gaw Karen:ခၣ်(khà)
- Western Pwo:ခၪ
- Western Kayah:ꤋꤢꤧ꤬(hkàe)
- *m-sin(“liver, heart, bile, bitter”)
- *m-ka(“mouth, opening, door”)
- *ka(“word, speech, language”)
- *tsa(“salt”)
