| Caac | msq | Living |
| Cabécar | cjp | Living |
| Cabiyarí | cbb | Living |
| Cacaloxtepec Mixtec | miu | Living |
| Cacaopera | ccr | Extinct |
| Cacgia Roglai | roc | Living |
| Cacua | cbv | Living |
| Caddo | cad | Living |
| Cafundo Creole | ccd | Living |
| Cagua | cbh | Extinct |
| Cahuarano | cah | Living |
| Cahuilla | chl | Living |
| Cahungwarya | nat | Living |
| Cajamarca Quechua | qvc | Living |
| Cajatambo North Lima Quechua | qvl | Living |
| Cajonos Zapotec | zad | Living |
| Cajun French | frc | Living |
| Caka | ckx | Living |
| Cakchiquel-Quiché Mixed Language | ckz | Living |
| Cakfem-Mushere | cky | Living |
| Calamian Tagbanwa | tbk | Living |
| Calderón Highland Quichua | qud | Living |
| Callawalla | caw | Living |
| Caló | rmq | Living |
| Caluyanun | clu | Living |
| Cameroon Mambila | mcu | Living |
| Cameroon Pidgin | wes | Living |
| Camling | rab | Living |
| Campalagian | cml | Living |
| Campidanese Sardinian | sro | Living |
| Camsá | kbh | Living |
| Camtho | cmt | Living |
| Camunic | xcc | Ancient |
| Cañar Highland Quichua | qxr | Living |
| Candoshi-Shapra | cbu | Living |
| Canela | ram | Living |
| Canichana | caz | Extinct |
| Cao Lan | mlc | Living |
| Cao Miao | cov | Living |
| Capanahua | kaq | Living |
| Capiznon | cps | Living |
| Cappadocian Greek | cpg | Extinct |
| Caquinte | cot | Living |
| Car Nicobarese | caq | Living |
| Cara | cfd | Living |
| Carabayo | cby | Living |
| Caramanta | crf | Extinct |
| Carapana | cbc | Living |
| Carian | xcr | Ancient |
| Caribbean Hindustani | hns | Living |
| Caribbean Javanese | jvn | Living |
| Carijona | cbd | Living |
| Carolina Algonquian | crr | Extinct |
| Carolinian | cal | Living |
| Carpathian Romani | rmc | Living |
| Carrier | crx | Living |
| Cashibo-Cacataibo | cbr | Living |
| Cashinahua | cbs | Living |
| Casiguran Dumagat Agta | dgc | Living |
| Casuarina Coast Asmat | asc | Living |
| Catalan | cat | Living |
| Catalan Sign Language | csc | Living |
| Catawba | chc | Extinct |
| Cauca | cca | Extinct |
| Cavineña | cav | Living |
| Cayubaba | cyb | Extinct |
| Cayuga | cay | Living |
| Cayuse | xcy | Extinct |
| Cebaara Senoufo | sef | Living |
| Cebuano | ceb | Living |
| Celtiberian | xce | Ancient |
| Cemuhî | cam | Living |
| Cen | cen | Living |
| Central Asmat | cns | Living |
| Central Atlas Tamazight | tzm | Living |
| Central Awyu | awu | Living |
| Central Aymara | ayr | Living |
| Central Bai | bca | Living |
| Central Berawan | zbc | Living |
| Central Bikol | bcl | Living |
| Central Bontok | lbk | Living |
| Central Cagayan Agta | agt | Living |
| Central Dusun | dtp | Living |
| Central Grebo | grv | Living |
| Central Hongshuihe Zhuang | zch | Living |
| Central Huasteca Nahuatl | nch | Living |
| Central Huishui Hmong | hmc | Living |
| Central Kanuri | knc | Living |
| Central Khmer | khm | Living |
| Central Kurdish | ckb | Living |
| Central Maewo | mwo | Living |
| Central Malay | pse | Living |
| Central Masela | mxz | Living |
| Central Mashan Hmong | hmm | Living |
| Central Mazahua | maz | Living |
| Central Melanau | mel | Living |
| Central Mnong | cmo | Living |
| Central Nahuatl | nhn | Living |
| Central Nicobarese | ncb | Living |
| Central Ojibwa | ojc | Living |
| Central Okinawan | ryu | Living |
| Central Palawano | plc | Living |
| Central Pame | pbs | Living |
| Central Pashto | pst | Living |
| Central Pomo | poo | Living |
| Central Puebla Nahuatl | ncx | Living |
| Central Sama | sml | Living |
| Central Siberian Yupik | ess | Living |
| Central Sierra Miwok | csm | Living |
| Central Subanen | syb | Living |
| Central Tagbanwa | tgt | Living |
| Central Tarahumara | tar | Living |
| Central Tunebo | tuf | Living |
| Central Yupik | esu | Living |
| Central-Eastern Niger Fulfulde | fuq | Living |
| Centúúm | cet | Living |
| Cerma | cme | Living |
| Chabu | sbf | Living |
| Chachapoyas Quechua | quk | Living |
| Chachi | cbi | Living |
| Chácobo | cao | Living |
| Chadian Arabic | shu | Living |
| Chadian Sign Language | cds | Living |
| Chadong | cdy | Living |
| Chagatai | chg | Extinct |
| Chaima | ciy | Living |
| Chak | ckh | Living |
| Chakali | cli | Living |
| Chakma | ccp | Living |
| Chala | cll | Living |
| Chaldean Neo-Aramaic | cld | Living |
| Chalikha | tgf | Living |
| Chamacoco | ceg | Living |
| Chamalal | cji | Living |
| Chamari | cdg | Living |
| Chambeali | cdh | Living |
| Chambri | can | Living |
| Chamicuro | ccc | Living |
| Chamorro | cha | Living |
| Chané | caj | Extinct |
| Chang Naga | nbc | Living |
| Changriwa | cga | Living |
| Changthang | cna | Living |
| Chantyal | chx | Living |
| Chara | cra | Living |
| Chaudangsi | cdn | Living |
| Chaura | crv | Living |
| Chavacano | cbk | Living |
| Chayahuita | cbt | Living |
| Chayuco Mixtec | mih | Living |
| Chazumba Mixtec | xtb | Living |
| Che | ruk | Living |
| Chechen | che | Living |
| Cheke Holo | mrn | Living |
| Chemakum | xch | Extinct |
| Chenapian | cjn | Living |
| Chenchu | cde | Living |
| Chenoua | cnu | Living |
| Chepang | cdm | Living |
| Chepya | ycp | Living |
| Cherepon | cpn | Living |
| Cherokee | chr | Living |
| Chesu | ych | Living |
| Chetco | ctc | Living |
| Chewong | cwg | Living |
| Cheyenne | chy | Living |
| Chhattisgarhi | hne | Living |
| Chhintange | ctn | Living |
| Chhulung | cur | Living |
| Chiangmai Sign Language | csd | Living |
| Chiapanec | cip | Living |
| Chibcha | chb | Extinct |
| Chicahuaxtla Triqui | trs | Living |
| Chichicapan Zapotec | zpv | Living |
| Chichimeca-Jonaz | pei | Living |
| Chickasaw | cic | Living |
| Chicomuceltec | cob | Extinct |
| Chiga | cgg | Living |
| Chigmecatitlán Mixtec | mii | Living |
| Chilcotin | clc | Living |
| Chilean Quechua | cqu | Living |
| Chilean Sign Language | csg | Living |
| Chilisso | clh | Living |
| Chiltepec Chinantec | csa | Living |
| Chimalapa Zoque | zoh | Living |
| Chimariko | cid | Extinct |
| Chimborazo Highland Quichua | qug | Living |
| Chimila | cbg | Living |
| China Buriat | bxu | Living |
| Chinali | cih | Living |
| Chinbon Chin | cnb | Living |
| Chincha Quechua | qxc | Living |
| Chinese | zho | Living |
| Chinese Pidgin English | cpi | Living |
| Chinese Sign Language | csl | Living |
| Chinook | chh | Living |
| Chinook jargon | chn | Living |
| Chipaya | cap | Living |
| Chipewyan | chp | Living |
| Chipiajes | cbe | Extinct |
| Chippewa | ciw | Living |
| Chiquián Ancash Quechua | qxa | Living |
| Chiquihuitlán Mazatec | maq | Living |
| Chiquitano | cax | Living |
| Chiripá | nhd | Living |
| Chiru | cdf | Living |
| Chitimacha | ctm | Extinct |
| Chitkuli Kinnauri | cik | Living |
| Chittagonian | ctg | Living |
| Chitwania Tharu | the | Living |
| Choapan Zapotec | zpc | Living |
| Chocangacakha | cgk | Living |
| Chochotec | coz | Living |
| Choctaw | cho | Living |
| Chodri | cdi | Living |
| Chokri Naga | nri | Living |
| Chokwe | cjk | Living |
| Chol | ctu | Living |
| Cholón | cht | Extinct |
| Chong | cog | Living |
| Choni | cda | Living |
| Chonyi-Dzihana-Kauma | coh | Living |
| Chopi | cce | Living |
| Chorasmian | xco | Ancient |
| Chortí | caa | Living |
| Chothe Naga | nct | Living |
| Chrau | crw | Living |
| Chru | cje | Living |
| Chuanqiandian Cluster Miao | cqd | Living |
| Chuave | cjv | Living |
| Chug | cvg | Living |
| Chuj | cac | Living |
| Chuka | cuh | Living |
| Chukot | ckt | Living |
| Chukwa | cuw | Living |
| Chulym | clw | Living |
| Chumburung | ncu | Living |
| Churahi | cdj | Living |
| Church Slavic | chu | Ancient |
| Chut | scb | Living |
| Chuukese | chk | Living |
| Chuvantsy | xcv | Extinct |
| Chuvash | chv | Living |
| Chuwabu | chw | Living |
| Ci Gbe | cib | Living |
| Cia-Cia | cia | Living |
| Cibak | ckl | Living |
| Cicipu | awc | Living |
| Cimbrian | cim | Living |
| Cinda-Regi-Tiyal | cdr | Living |
| Cineni | cie | Living |
| Cinta Larga | cin | Living |
| Cisalpine Gaulish | xcg | Ancient |
| Cishingini | asg | Living |
| Citak | txt | Living |
| Ciwogai | tgd | Living |
| Clallam | clm | Living |
| Classical Armenian | xcl | Historic |
| Classical Mandaic | myz | Historic |
| Classical Mongolian | cmg | Historic |
| Classical Nahuatl | nci | Historic |
| Classical Newari | nwc | Historic |
| Classical Quechua | qwc | Historic |
| Classical Syriac | syc | Historic |
| Classical Tibetan | xct | Historic |
| C’lela | dri | Living |
| Coahuilteco | xcw | Extinct |
| Coast Miwok | csi | Extinct |
| Coastal Kadazan | kzj | Living |
| Coastal Konjo | kjc | Living |
| Coatecas Altas Zapotec | zca | Living |
| Coatepec Nahuatl | naz | Living |
| Coatlán Mixe | mco | Living |
| Coatlán Zapotec | zps | Living |
| Coatzospan Mixtec | miz | Living |
| Cocama-Cocamilla | cod | Living |
| Cochimi | coj | Extinct |
| Cocopa | coc | Living |
| Cocos Islands Malay | coa | Living |
| Coeur d’Alene | crd | Living |
| Cofán | con | Living |
| Cogui | kog | Living |
| Col | liw | Living |
| Colombian Sign Language | csn | Living |
| Colonia Tovar German | gct | Living |
| Colorado | cof | Living |
| Columbia-Wenatchi | col | Living |
| Comaltepec Chinantec | cco | Living |
| Comanche | com | Living |
| Comecrudo | xcm | Extinct |
| Como Karim | cfg | Living |
| Comox | coo | Living |
| Con | cno | Living |
| Congo Swahili | swc | Living |
| Côông | cnc | Living |
| Coos | csz | Living |
| Copainalá Zoque | zoc | Living |
| Copala Triqui | trc | Living |
| Coptic | cop | Extinct |
| Coquille | coq | Extinct |
| Cori | cry | Living |
| Cornish | cor | Living |
| Corongo Ancash Quechua | qwa | Living |
| Corsican | cos | Living |
| Costa Rican Sign Language | csr | Living |
| Cotabato Manobo | mta | Living |
| Cotoname | xcn | Extinct |
| Cowlitz | cow | Extinct |
| Coxima | kox | Extinct |
| Coyaima | coy | Extinct |
| Coyotepec Popoloca | pbf | Living |
| Coyutla Totonac | toc | Living |
| Cree | cre | Living |
| Creek | mus | Living |
| Crimean Tatar | crh | Living |
| Croatia Sign Language | csq | Living |
| Croatian | hrv | Living |
| Cross River Mbembe | mfn | Living |
| Crow | cro | Living |
| Cruzeño | crz | Extinct |
| Cua | cua | Living |
| Cuba Sign Language | csf | Living |
| Cubeo | cub | Living |
| Cuiba | cui | Living |
| Culina | cul | Living |
| Cumanagoto | cuo | Extinct |
| Cumbric | xcb | Extinct |
| Cumeral | cum | Extinct |
| Cun | cuq | Living |
| Cuneiform Luwian | xlu | Ancient |
| Cung | cug | Living |
| Cupeño | cup | Extinct |
| Curonian | xcu | Extinct |
| Curripaco | kpc | Living |
| Cusco Quechua | quz | Living |
| Cutchi-Swahili | ccl | Living |
| Cuvok | cuv | Living |
| Cuyamecalco Mixtec | xtu | Living |
| Cuyonon | cyo | Living |
| Cwi Bwamu | bwy | Living |
| Cypriot Arabic | acy | Living |
| Czech | ces | Living |
| Czech Sign Language | cse | Living |