| bpaDaakaka | bpa | Austronesian | | | 6a · Vigorous |
| lniDaantanai’ | lni | South Bougainville | | | 6a · Vigorous |
| dshDaasanach | dsh | Afroasiatic | | 60,500 | 5 · Developing |
| dtnDaats’íin | dtn | — | | | 6a · Vigorous |
| dbqDaba | dbq | Afroasiatic | | | 5 · Developing |
| dbeDabebahasa Dabe | dbe | Orya–Tor | | | 7 · Shifting |
| ddaDadi Dadi | dda | Australian Aboriginal languages | | | 9 · Dormant |
| dbdDadiya | dbd | — | | 70,000 | 6a · Vigorous |
| dgzDaga | dgz | Dagan | | | 5 · Developing |
| dgaDagaare | dga | Niger–Congo | | 1.1 m | 4 · Educational |
| dgdDagaari Dioula | dgd | Niger–Congo | | | 6a · Vigorous |
| dgkDagba | dgk | Nilo-Saharan | | | 6a · Vigorous |
| dagDagbanli | dag | Niger–Congo | | 4.2 m | 4 · Educational |
| dgnDagoman | dgn | — | | | 10 · Extinct |
| dlkDahalik | dlk | Afroasiatic | | 2,500 | 6b · Threatened |
| dalDahalo | dal | Afroasiatic | | 400 | 8a · Moribund |
| dasDaho-Doo | das | Niger–Congo | | | 6b · Threatened |
| dijDai | dij | — | | | 6b · Threatened |
| daoDai | dao | Sino-Tibetan | | | 5 · Developing |
| drbDair | drb | Nilo-Saharan | | | 8a · Moribund |
| btdDairi | btd | Austronesian | | | 6b · Threatened |
| dkkDakkabahasa Dakka | dkk | Austronesian | | | 7 · Shifting |
| dakDakotaDakhód'iapi | dak | Hoka-Sioux | | 3,100 | 7 · Shifting |
| dkaDakpa | dka | Bodish | | | 6b · Threatened |
| ngkDalabon | ngk | Australian Aboriginal languages | | | 8b · Nearly Extinct |
| dlmDalmatian | dlm | Indo-European | | | Extinct |
| dmmDama | dmm | Niger–Congo | | | 8a · Moribund |
| damDamakawa | dam | Niger–Congo | | | 9 · Dormant |
| idbDaman Creole Portuguese | idb | — | | 4,180 | 6b · Threatened |
| dmrDamar Timur | dmr | — | | 400 | 6b · Threatened |
| dacDambi | dac | Austronesian | | | 6b · Threatened |
| dmlDameli | dml | — | | | 6a · Vigorous |
| dmsDampelasbahasa Dampelas | dms | Austronesian | | | 7 · Shifting |
| dnjDan | dnj | Niger–Congo | | | 5 · Developing |
| dnuDanau | dnu | Austroasiatic | | | 6b · Threatened |
| beaDane-zaa | bea | Na-Dene | | 160 | 8a · Moribund |
| daaDangaléat | daa | Afroasiatic | | | 5 · Developing |
| thlDangaura Tharu | thl | Indo-European | | | 5 · Developing |
| adaDangme | ada | Niger–Congo | | | 4 · Educational |
| danDanishdansk | dan | East Scandinavian | +1 | 5.5 m | 1 · National |
| dazDao | daz | Trans–New Guinea | | | 6b · Threatened |
| dndDaonda | dnd | Border | | | 6b · Threatened |
| darDargwaдарган мез | dar | Northeast Caucasian | | | 4 · Educational |
| prsDariدری | prs | Indo-European | | 9.6 m | 1 · National |
| xdaDarkinjung | xda | Australian Aboriginal languages | | | 9 · Dormant |
| drlDarling | drl | Australian Aboriginal languages | | 110 | 8b · Nearly Extinct |
| drdDarmiya | drd | — | | | 6b · Threatened |
| droDaro-Matu | dro | Austronesian | | | 6b · Threatened |
| xgmDarumbal | xgm | Australian Aboriginal languages | | | 9 · Dormant |
| dotDass | dot | Afroasiatic | | 37,582 | 6a · Vigorous |
| tccDatooga | tcc | Nilo-Saharan | | | 5 · Developing |
| dgwDaungwurrung | dgw | Australian Aboriginal languages | | | 9 · Dormant |
| dtaDaur | dta | Mongolic | | 96,085 | 7 · Shifting |
| dawDavaoan language | daw | Austronesian | | | 6a · Vigorous |
| kwaDâw | kwa | Nadahup | | 142 | 6a · Vigorous |
| dwwDawawa | dww | Austronesian | | | 5 · Developing |
| dmkDawoodiداوودی | dmk | Indo-European | | | 8b · Nearly Extinct |
| daiDay | dai | Niger–Congo | | | 6a · Vigorous |
| daxDayi | dax | Australian Aboriginal languages | | | 7 · Shifting |
| dzgDazaga-kara | dzg | Nilo-Saharan | | | 3 · Wider Communication |
| afnDefaka | afn | Niger–Congo | | | 8b · Nearly Extinct |
| mzwDeg | mzw | Niger–Congo | | | 5 · Developing |
| ingDeg Xinag | ing | Na-Dene | | 40 | 8b · Nearly Extinct |
| degDegema | deg | Niger–Congo | | | 6a · Vigorous |
| dgeDegenan | dge | Trans–New Guinea | | | 6a · Vigorous |
| dehDehwari | deh | Indo-European | | | 6a · Vigorous |
| dekDek | dek | Niger–Congo | | | 6b · Threatened |
| rowDela-Oenalebahasa Dela-Oenale | row | Austronesian | | | 6a · Vigorous |
| delDelaware | del | Algic | | | |
| ntrDelo | ntr | — | | | 5 · Developing |
| demDembahasa Dem | dem | — | | | 6b · Threatened |
| dmxDema | dmx | Niger–Congo | | | 6b · Threatened |
| deiDemisabahasa Demisa | dei | Geelvink Bay | | | 6b · Threatened |
| dmyDemtabahasa Demta | dmy | Sentani | | | 8a · Moribund |
| tfnDena'inaDenaʼina Qenaga | tfn | Na-Dene | | 75 | 7 · Shifting |
| deqDendi | deq | Niger–Congo | | 10,000 | 6a · Vigorous |
| ddnDendi | ddn | Nilo-Saharan | | 32,050 | 3 · Wider Communication |
| dezDengese | dez | Niger–Congo | | | 6a · Vigorous |
| dnkDengkabahasa Dengka | dnk | — | | | 6a · Vigorous |
| dnyDeni | dny | Arawan | | 740 | 5 · Developing |
| dbbDeno | dbb | Afroasiatic | | | 6a · Vigorous |
| anvDenya | anv | Niger–Congo | | | 5 · Developing |
| derDeori | der | Sino-Tibetan | | | 5 · Developing |
| kbvDerabahasa Dera | kbv | — | | | 6b · Threatened |
| duuDerung | duu | Sino-Tibetan | | 14,225 | 6a · Vigorous |
| desDesanoWiná | des | Tucanoan | | 6,000 | 6b · Threatened |
| dsoDesiya | dso | — | | | 3 · Wider Communication |
| deeDewoin | dee | Niger–Congo | | | 6a · Vigorous |
| dunDeyah | dun | Austronesian | | 20,000 | 6a · Vigorous |
| defDezfuli | def | — | | | 8b · Nearly Extinct |
| dghDghwede | dgh | — | | | 6a · Vigorous |
| dhsDhaiso | dhs | Niger–Congo | | | 7 · Shifting |
| dhlDhalandji | dhl | Australian Aboriginal languages | | | 8b · Nearly Extinct |
| dhgDhangu | dhg | Australian Aboriginal languages | | 310 | 6b · Threatened |
| dhwDhanwar Rai | dhw | Indo-European | | | 6b · Threatened |
| nfaDhaobahasa Dhao | nfa | Austronesian | | | 5 · Developing |
| dhrDhargari | dhr | Australian Aboriginal languages | | | 9 · Dormant |
| xdkDharug | xdk | Australian Aboriginal languages | | | 9 · Dormant |
| mkiDhatki | mki | Indo-European | | 150,000 | 5 · Developing |
| gjmDhauwurd Wurrung | gjm | Australian Aboriginal languages | | | 10 · Extinct |
| dhiDhimal | dhi | Sino-Tibetan | | | 6b · Threatened |
| ditDhirari | dit | Australian Aboriginal languages | | | 10 · Extinct |
| adfDhofari Arabic | adf | Afroasiatic | | | 6a · Vigorous |
| luoDholuo | luo | Nilo-Saharan | | 3 m | 5 · Developing |
| ddrDhudhuroa | ddr | Australian Aboriginal languages | | | |
| dhdDhundari | dhd | Indo-European | | 9.6 m | 5 · Developing |
| dhxDhungaloo | dhx | Australian Aboriginal languages | | | 9 · Dormant |
| dhuDhurga | dhu | Australian Aboriginal languages | | | 9 · Dormant |
| dwyDhuwaya | dwy | Australian Aboriginal languages | | | 4 · Educational |
| diaDia | dia | Torricelli | | | 6a · Vigorous |
| mbdDibabawon Manobo | mbd | Austronesian | | | 5 · Developing |
| bvxDibole | bvx | Niger–Congo | | | 6a · Vigorous |
| duyDicamay Agta | duy | — | | | 10 · Extinct |
| difDieri | dif | Australian Aboriginal languages | | | 8b · Nearly Extinct |
| mhuDigaro Mishmi | mhu | Sino-Tibetan | | | 6a · Vigorous |
| digDigo | dig | Niger–Congo | | | 5 · Developing |
| osdDigor Ossetianдыгурон диалект | osd | Indo-European | | 100,000 | |
| durDii | dur | Niger–Congo | | | 5 · Developing |
| cfaDijim-Bwilim | cfa | — | | 25,000 | 5 · Developing |
| dilDilling | dil | Nilo-Saharan | | | 8a · Moribund |
| disDimasa | dis | Sino-Tibetan | | | 5 · Developing |
| dimDime | dim | Afroasiatic | | | 6a · Vigorous |
| mrxDineorbahasa Maremgi | mrx | Orya–Tor | | | 8a · Moribund |
| dizDing | diz | Niger–Congo | | | 6a · Vigorous |
| dinDinkaThuɔŋjäŋ | din | Nilo-Saharan | | 1.4 m | |
| ddiDiodio | ddi | Austronesian | | 2,200 | 6a · Vigorous |
| gdlDirasha | gdl | Afroasiatic | | 65,000 | |
| dwaDiri | dwa | Afroasiatic | | 7,200 | 6a · Vigorous |
| dirDirim | dir | Niger–Congo | | | 6b · Threatened |
| dsiDisa | dsi | Nilo-Saharan | | | 6b · Threatened |
| dtdDitidaht | dtd | Wakashan | | | 8b · Nearly Extinct |
| diyDiuwebahasa Diuwe | diy | — | | | 6b · Threatened |
| mdxDizin | mdx | Dizoid | | | 4 · Educational |
| dybDjabirr-Djabirr | dyb | Nyulnyulan | | | 10 · Extinct |
| dyyDjabugay | dyy | Australian Aboriginal languages | | | 8a · Moribund |
| tjwDjabwurrung | tjw | Australian Aboriginal languages | | | 9 · Dormant |
| djaDjadjawurrung | dja | Australian Aboriginal languages | | | 10 · Extinct |
| djrDjambarrpuyngu | djr | Australian Aboriginal languages | | 2,766 | 3 · Wider Communication |
| djfDjangun | djf | Australian Aboriginal languages | | | 10 · Extinct |
| ddjDjaru | ddj | Ngumbin | | | 7 · Shifting |
| djnDjauan | djn | Australian Aboriginal languages | | | 8b · Nearly Extinct |
| djwDjawi | djw | Nyulnyulan | | | 10 · Extinct |
| djjDjeebbana | djj | Maningrida | | | 6b · Threatened |
| dyiDjimini | dyi | Niger–Congo | | | 5 · Developing |
| djiDjinang | dji | Australian Aboriginal languages | | | 6b · Threatened |
| djbDjinba | djb | Australian Aboriginal languages | | | 6b · Threatened |
| dydDjugun | dyd | Nyulnyulan | | | 10 · Extinct |
| kvoDobel | kvo | Austronesian | | 2,000 | 5 · Developing |
| dobDobu | dob | Austronesian | | | 3 · Wider Communication |
| doeDoe | doe | Niger–Congo | | 24,000 | 6a · Vigorous |
| dggDoga | dgg | Austronesian | | | 6b · Threatened |
| dgxDoghoro | dgx | Trans–New Guinea | | | 6b · Threatened |
| dgoDogriडोगरी | dgo | Indo-European | | 2 m | 4 · Educational |
| dgrDogribTłı̨chǫ Yatıı̀ | dgr | Na-Dene | | 1,735 | 6b · Threatened |
| dbgDogul Dogon | dbg | Niger–Congo | | | 6a · Vigorous |
| dbiDoka | dbi | Niger–Congo | | | 6a · Vigorous |
| dlgDolganдолган | dlg | Turkic | | 4,836 | 6b · Threatened |
| dreDolpo | dre | — | | | 5 · Developing |
| rmtDomari | rmt | Indo-European | | 1.3 m | 7 · Shifting |
| dovDombe | dov | Niger–Congo | | 5,430 | 6a · Vigorous |
| doqDominican Sign Language | doq | — | | | 5 · Developing |
| doyDompo | doy | Niger–Congo | | | 8a · Moribund |
| dofDomu | dof | Trans–New Guinea | | | 6a · Vigorous |
| devDomung | dev | Trans–New Guinea | | | 6a · Vigorous |
| dokDondo | dok | Austronesian | | | 6b · Threatened |
| dohDonga | doh | Niger–Congo | | | 6a · Vigorous |
| dooDongo | doo | Niger–Congo | | | 6a · Vigorous |
| dglDongolawi | dgl | Nilo-Saharan | | | 6b · Threatened |
| dddDongotono | ddd | Nilo-Saharan | | | 6b · Threatened |
| ddeDoondo | dde | Niger–Congo | | | 6a · Vigorous |
| dorDori'o | dor | Austronesian | | | 6a · Vigorous |
| wwoDorig | wwo | Austronesian | | | 6a · Vigorous |
| drrDororo | drr | Austronesian | | | 10 · Extinct |
| dozDorze | doz | Afroasiatic | | | 6b · Threatened |
| dolDoso | dol | — | | | 6b · Threatened |
| dtyDoteliडोटेली | dty | Indo-European | | 790,000 | 6a · Vigorous |
| tdsDoutaibahasa Doutai | tds | Lakes Plain | | | 7 · Shifting |
| dowDowayo | dow | — | | 18,000 | 5 · Developing |
| drtDrèents | drt | Indo-European | | 255,000 | 5 · Developing |
| dhvDrehu | dhv | Austronesian | | 15,949 | 4 · Educational |
| duaDuala | dua | Niger–Congo | | | 3 · Wider Communication |
| dupDuano’bahasa Duano | dup | Austronesian | | | 6a · Vigorous |
| dvaDuau | dva | Austronesian | | | 6a · Vigorous |
| dubDubli | dub | Indo-European | | | 6b · Threatened |
| dbmDuguri | dbm | Niger–Congo | | 65,000 | 6b · Threatened |
| kbzDuhwa | kbz | Afroasiatic | | | 6b · Threatened |
| nkeDuke | nke | Austronesian | | | 6a · Vigorous |
| dboDulbu | dbo | Niger–Congo | | | 8b · Nearly Extinct |
| tdeDuleri Dogon | tde | Niger–Congo | | | 6a · Vigorous |
| duzDuli | duz | Niger–Congo | | | 9 · Dormant |
| dmaDuma | dma | Niger–Congo | | | 6a · Vigorous |
| dgcDumagat Agta | dgc | Austronesian | | | 5 · Developing |
| dusDumi | dus | Sino-Tibetan | | | 6b · Threatened |
| duiDumun | dui | Trans–New Guinea | | | 6b · Threatened |
| dngDungan | dng | Sino-Tibetan | | 41,400 | 7 · Shifting |
| raaDungmali | raa | Sino-Tibetan | | | 6b · Threatened |
| duhDungra Bhil | duh | Indo-European | | | 5 · Developing |
| duoDupaningan Agta | duo | Austronesian | | | 6b · Threatened |
| drqDura | drq | Sino-Tibetan | | | 9 · Dormant |
| mvpDuri | mvp | Austronesian | | | 5 · Developing |
| dbnDuriankerebahasa Duriankere | dbn | — | | | 8a · Moribund |
| pciDuruwa | pci | — | | | 6a · Vigorous |
| dsnDusnerbahasa Dusner | dsn | Austronesian | | | 9 · Dormant |
| duqDusun Malang | duq | Austronesian | | 4,500 | 6b · Threatened |
| duwDusun Witubahasa Dusun Witu | duw | Austronesian | | | 6b · Threatened |
| nldDutchNederlands | nld | Indo-European | +6 | 23.1 m | 1 · National |
| dseDutch Sign Language | dse | — | | 15,000 | 5 · Developing |
| duxDuungooma | dux | Niger–Congo | | | 6a · Vigorous |
| daeDuupa | dae | — | | 5,000 | 5 · Developing |
| duvDuvlebahasa Duvde | duv | Lakes Plain | | | 6b · Threatened |
| gveDuwet | gve | Austronesian | | | 6b · Threatened |
| nnuDwang | nnu | Niger–Congo | | | 6a · Vigorous |
| dyaDyan | dya | Niger–Congo | | | 6a · Vigorous |
| dynDyangadi | dyn | Australian Aboriginal languages | | | 10 · Extinct |
| dblDyirbal | dbl | — | | 8 | 8a · Moribund |
| dyuDyula | dyu | Niger–Congo | | 2.7 m | 3 · Wider Communication |
| dzlDzala | dzl | Bodish | | | 6a · Vigorous |
| dznDzando | dzn | Niger–Congo | | | 6a · Vigorous |
| bpnDzao Min | bpn | Hmong–Mien | | | 6a · Vigorous |
| dzoDzongkhaརྫོང་ཁ་ | dzo | Southern Tibetic | | 237,080 | 1 · National |