| Name | Other Name | Family | Nativ Name | ISO6391 Code | ISO6392T Code | ISO6392B Code | ISO6393 Code | Notes |
|---|---|---|---|---|---|---|---|---|
| Korean | Koreanic | 한국어 | ko | kor | kor | kor | ||
| Kuanyama | Kwanyama | Niger–Congo | Kuanyama | kj | kua | kua | kua | |
| Kurdish | Indo-European | Kurdî; كوردی | ku | kur | kur | kur + 3 | macrolanguage | |
| Lao | Tai–Kadai | ພາສາລາວ | lo | lao | lao | lao | ||
| Latin | Indo-European | latine; lingua latina | la | lat | lat | lat | ancient | |
| Latvian | Indo-European | latviešu valoda | lv | lav | lav | lav + 2 | macrolanguage | |
| Limburgan | Limburger;Limburgish | Indo-European | Limburgs | li | lim | lim | lim | |
| Lingala | Niger–Congo | Lingála | ln | lin | lin | lin | ||
| Lithuanian | Indo-European | lietuvių kalba | lt | lit | lit | lit | ||
| Luxembourgish | Letzeburgesch | Indo-European | Lëtzebuergesch | lb | ltz | ltz | ltz |