| Name | Other Name | Family | Nativ Name | ISO6391 Code | ISO6392T Code | ISO6392B Code | ISO6393 Code | Notes |
|---|---|---|---|---|---|---|---|---|
| Breton | Indo-European | brezhoneg | br | bre | bre | bre | ||
| Bulgarian | Indo-European | български език | bg | bul | bul | bul | ||
| Catalan | Valencian | Indo-European | català; valencià | ca | cat | cat | cat | |
| Czech | Indo-European | čeština; český jazyk | cs | ces | cze | ces | ||
| Chamorro | Austronesian | Chamoru | ch | cha | cha | cha | ||
| Chechen | Northeast Caucasian | нохчийн мотт | ce | che | che | che | ||
| Church Slavic | Church Slavonic;Old Church Slavonic;Old Slavonic;Old Bulgarian | Indo-European | ѩзыкъ словѣньскъ | cu | chu | chu | chu | ancient; in use by Orthodox Church |
| Chuvash | Turkic | чӑваш чӗлхи | cv | chv | chv | chv | ||
| Cornish | Indo-European | Kernewek | kw | cor | cor | cor | ||
| Corsican | Indo-European | corsu; lingua corsa | co | cos | cos | cos |