| Name | Other Name | Family | Nativ Name | ISO6391 Code | ISO6392T Code | ISO6392B Code | ISO6393 Code | Notes |
|---|---|---|---|---|---|---|---|---|
| Georgian | South Caucasian | ქართული | ka | kat | geo | kat | ||
| Kanuri | Nilo-Saharan | Kanuri | kr | kau | kau | kau + 3 | macrolanguage | |
| Kazakh | Turkic | қазақ тілі | kk | kaz | kaz | kaz | ||
| Central Khmer | Austroasiatic | ខ្មែរ; ខេមរភាសា; ភាសាខ្មែរ | km | khm | khm | khm | also known as Khmer or Cambodian | |
| Kikuyu | Gikuyu | Niger–Congo | Gĩkũyũ | ki | kik | kik | kik | |
| Kinyarwanda | Niger–Congo | Ikinyarwanda | rw | kin | kin | kin | ||
| Kirghiz | Kyrgyz | Turkic | Кыргызча; Кыргыз тили | ky | kir | kir | kir | |
| Komi | Uralic | коми кыв | kv | kom | kom | kom + 2 | macrolanguage | |
| Kongo | Niger–Congo | Kikongo | kg | kon | kon | kon + 3 | macrolanguage | |
| Korean | Koreanic | 한국어 | ko | kor | kor | kor |