| Abbreviation | Definition |
|---|---|
| CAS | Central Asia |
| CAT | Catalan |
| CAU | Caucasian (Other) |
| CBV | CACUA: A Language of Colombia |
| CC | Control C |
| CEB | Cebuano |
| CEL | Celtic (Other) |
| CES | Czech |
| CGI | East Canada, Greenland and Iceland |
| CGL | Classical Greek and Latin |
| CHA | Chamorro |
| CHB | Chibcha |
| CHE | Chechen |
| CHG | Chagatai |
| CHI | Chinese |
| CHM | Mari |
| CHN | Chinook jargon |
| CHO | Choctaw |
| CHR | Cherokee |
| CHU | Church Slavic |