- For an explanation of these codes see ISO 639-3.
| 639-3 | 639-1 | 639-2B | Scope/Type | Family | Native | eng | fra | spa | zho | rus | deu |
| uam | | | I/E | | | Uamué | | | | | |
| uan | | | I/L | | | Kuan | | | | | |
| uar | | | I/L | | | Tairuma | | | | | |
| uba | | | I/L | | | Ubang | | | | | |
| ubi | | | I/L | | | Ubi | | | | | |
| ubr | | | I/L | | | Ubir | | | | | Ubir |
| ubu | | | I/L | | | Umbu-Ungu | | | | | |
| uby | | | I/E | | atʷaχəbza | Ubykh | oubykh | ubijé | 尤比克语 | убыхский | |
| uda | | | I/L | | | Uda | | | | | |
| ude | | | I/L | | | Udihe | | | 乌德语 | | |
| udg | | | I/L | | | Muduga | | | | | |
| udi | | | I/L | | удин | Udi | oudi | udi | | | |
| udj | | | I/L | | | Ujir | | | | | Ujir |
| udl | | | I/L | | | Wuzlam | | | | | |
| udm | | udm | I/L | | удмурт | Udmurt | oudmourte | udmurto | 乌德穆尔特语 | удмуртский | Udmurtisch |
| udu | | | I/L | | | Uduk | | | | | |
| ues | | | I/L | | | Kioko | | | | | |
| ufi | | | I/L | | | Ufim | | | | | |
| uga | | uga | I/A | | | Ugaritic | ougaritique | ugarítico | 乌加里特语 | угаритский | Ugaritisch |
| ugb | | | I/L | | | Kuku-Ugbanh | | | | | |
| uge | | | I/L | | | Ughele | | | | | |
| ugn | | | I/L | | | Ugandan Sign Language | | | 乌干达手语 | | Ugandische Zeichensprache |
| ugo | | | I/L | | | Ugong | | | | | |
| ugy | | | I/L | | | Uruguayan Sign Language | | | 乌拉圭手语 | | |
| uha | | | I/L | | | Uhami | | | | | |
| uhn | | | I/L | | | Damal | | | | | |
| uig | ug | uig | I/L | | ئۇيغۇرچە | Uighur | ouïgour | uigur | 维吾尔语 | уйгурский | Uigurisch |
| uis | | | I/L | | | Uisai | | | | | |
| uiv | | | I/L | | | Iyive | | | | | |
| uji | | | I/L | | | Tanjijili | | | | | |
| uka | | | I/L | | | Kaburi | | | | | |
| ukg | | | I/L | | | Ukuriguma | | | | | |
| ukh | | | I/L | | | Ukhwejo | | | | | |
| ukl | | | I/L | | | Ukrainian Sign Language | | | 乌克兰手语 | | Ukrainische Zeichensprache |
| ukp | | | I/L | | | Ukpe-Bayobiri | | | | | |
| ukq | | | I/L | | | Ukwa | | | | | |
| ukr | uk | ukr | I/L | | українська | Ukrainian | ukrainien | ucrani(an)o | 乌克兰语 | украинский | Ukrainisch |
| uks | | | I/L | | | Urubú-Kaapor Sign Language | | | | | |
| uku | | | I/L | | | Ukue | | | | | |
| ukw | | | I/L | | | Ukwuani-Aboh-Ndoni | | | | | |
| ula | | | I/L | | | Fungwa | | | | | |
| ulb | | | I/L | | | Ulukwumi | | | | | |
| ulc | | | I/L | | | Ulch | | | 乌利奇语 | ульчский | |
| ulf | | | I/L | | | Usku | | | | | |
| uli | | | I/L | | | Ulithian | ulithian | | | | |
| ulk | | | I/L | | | Meriam | | | | | |
| ull | | | I/L | | | Ullatan | | | | | |
| ulm | | | I/L | | | Ulumanda' | | | | | |
| uln | | | I/L | | | Unserdeutsch | unserdeutsch | | | | Unserdeutsch |
| ulu | | | I/L | | | Uma' Lung | | | | | |
| uma | | | I/L | | | Umatilla | | | | | |
| umb | | umb | I/L | | | Umbundu | umbundu | | 翁本杜语 | умбунду | |
| umc | | | I/A | | | Marrucinian | | | 马鲁西尼语 | | |
| umd | | | I/L | | | Umbindhamu | | | | | |
| umg | | | I/L | | | Umbuygamu | | | | | |
| umi | | | I/L | | | Ukit | | | | | |
| umm | | | I/L | | | Umon | | | | | |
| umn | | | I/L | | | Makyan Naga | | | | | |
| umo | | | I/E | | | Umotína | | | | | |
| ump | | | I/L | | | Umpila | | | | | |
| umr | | | I/L | | | Umbugarla | | | | | |
| ums | | | I/L | | | Pendau | | | | | |
| umu | | | I/L | | | Munsee | | | | | |
| una | | | I/L | | | Watut, North | | | | | |
| und | | und | O/S | * | | Undetermined | indéterminée | indeterminada | | неидентифицированный | |
| une | | | I/L | | | Uneme | | | | | |
| ung | | | I/L | | | Ngarinyin | | | | | |
| unk | | | I/L | | | Enawené-Nawé | | | | | |
| unm | | | I/E | | | Unami | | | | | |
| unp | | | I/L | | | Worora | | | | | |
| unr | | | I/L | | | Mundari | | | 蒙达里语 | | |
| unx | | | I/L | | | Munda | | | 蒙达语 | | |
| unz | | | I/L | | | Kaili, Unde | | | | | |
| uok | | | I/L | | | Uokha | | | | | |
| upi | | | I/L | | | Umeda | | | | | |
| upv | | | I/L | | | Uripiv-Wala-Rano-Atchin | | | | | |
| ura | | | I/L | | | Urarina | | | | | |
| urb | | | I/L | | | Urubú-Kaapor | | urubú-kaapor | | | |
| urc | | | I/L | | | Urningangg | | | | | |
| urd | ur | urd | I/L | | اردو | Urdu | ourdou | urdu | 乌尔都语; 乌都语; 晤鲁都语 | урду | Urdu |
| ure | | | I/L | | | Uru | | | | | |
| urf | | | I/L | | | Uradhi | | | | | |
| urg | | | I/L | | | Urigina | | | | | |
| urh | | | I/L | | | Urhobo | | | | | |
| uri | | | I/L | | | Urim | | | | | |
| urk | | | I/L | | | Urak Lawoi' | | | | | |
| url | | | I/L | | | Urali | | | | | |
| urm | | | I/L | | | Urapmin | | | | | |
| urn | | | I/L | | | Uruangnirin | | | | | |
| uro | | | I/L | | | Ura (Papua New Guinea) | | | | | |
| urp | | | I/L | | | Uru-Pa-In | | | | | |
| urr | | | I/L | | | Lehalurup | | | | | |
| urt | | | I/L | | | Urat | | | | | |
| uru | | | I/E | | | Urumi | | | | | |
| urv | | | I/E | | | Uruava | | | | | |
| urw | | | I/L | | | Sop | | | | | |
| urx | | | I/L | | | Urimo | | | | | |
| ury | | | I/L | | | Orya | | | | | |
| urz | | | I/L | | | Uru-Eu-Wau-Wau | | uru-eu-wau-wau | | | |
| usa | | | I/L | | | Usarufa | | | | | |
| ush | | | I/L | | | Ushojo | | | | | |
| usi | | | I/L | | | Usui | | | | | |
| usk | | | I/L | | | Usaghade | | | | | |
| usp | | | I/L | | | Uspanteco | | | | | |
| usu | | | I/L | | | Uya | | | | | |
| uta | | | I/L | | | Otank | | | | | |
| ute | | | I/L | | | Ute-Southern Paiute | ute | | | | |
| utp | | | I/L | | | Amba (Solomon Islands) | | | | | |
| utr | | | I/L | | | Etulo | | | | | |
| utu | | | I/L | | | Utu | | | | | |
| uum | | | I/L | | Урум | Urum | | | 乌鲁姆语 | | |
| uun | | | I/E | | | Kulon-Pazeh | | | 龟仑语; 巴宰语 | кулон-пазе | Kulon-Pazeh |
| uur | | | I/L | | | Ura (Vanuatu) | | | | | |
| uuu | | | I/L | | | U | | | 乌语 | | |
| uve | | | I/L | | | Uvean, West | | | | | |
| uvh | | | I/L | | | Uri | | | | | |
| uvl | | | I/L | | | Lote | | | | | |
| uwa | | | I/L | | | Kuku-Uwanh | | | | | |
| uya | | | I/L | | | Doko-Uyanga | | | | | |
| uzb | uz | uzb | M/L | | Ўзбек | Uzbek | ou(s)zbek | uzbeco | 乌兹别克语; 乌孜别克语 | узбекский | Usbekisch |
| uzn | | | I/L | | | Uzbek, Northern | | | 北乌兹别克语 | | |
| uzs | | | I/L | | | Uzbek, Southern | | | 南乌兹别克语 | | |