| Abbreviation | Definition |
|---|---|
| TWI | Twi |
| TYV | Tuvinian |
| TZN | Tugun |
| UAB | Uab Meto |
| UAE | United Arab Eremites |
| UDU | Uduk: a language of Ethiopia |
| UGA | Ugaritic |
| UGV | UMMOA Grammar and Vocabulary |
| UIG | Uighur |
| UKG | Ukuriguma |
| UKQ | Ukwa |
| UKR | Ukrainian |
| ULA | FUNGWA: A Language of Nigeria |
| ULK | MERIAM: A Language of Australia |
| UMB | Umbundu |
| UND | Undetermined |
| URD | Urdu |
| UZB | Uzbek |
| VAI | Vai |
| VAY | Wayu |