| Abbreviation | Definition |
|---|---|
| CHV | Chuvash |
| CHY | Cheyenne |
| CJK | Chinese Japanese And Korean |
| CKA | Chin, Khumi Awa |
| CNA | Central North America |
| COP | Coptic |
| COR | Cornish |
| COS | Corsican |
| CPE | Creoles and Pidgins, English-based (Other) |
| CPF | Creoles and Pidgins, French-based ( Other) |
| CPP | Creoles and Pidgins, Portuguese-based (Other) |
| CRE | Cree |
| CRF | Caramanta, an extinct language of Colombia |
| CRP | Creoles and Pidgins (Other) |
| CUS | Cushitic (Other) |
| CYM | Welsh |
| CZE | Czech |
| DAK | Dakota |
| DAN | Danish |
| DCG | Definite Clause Grammar |