| Date | Language or dialect | Language family | Region | Terminal speaker | Notes |
|---|
| 20th–21st century (?) | Ayabadhu | Pama-Nyungan | Queensland, Australia | | [68] |
| 20th–21st century (?) | Adithinngithigh | Pama-Nyungan | Queensland, Australia | | |
| 20th–21st century (?) | Arritinngithigh | Pama-Nyungan | Queensland, Australia | | |
| 1980–2000 | Tepecano | Uto-Aztecan | Central Mexico | Lino de la Rosa | Last known speaker was alive in 1980 |
| 1999 | Nyulnyul | Pama-Nyungan | Australia | Carmel Charles | [100] |
| 1998 | Mlahsô | Afroasiatic | Syria; Turkey | Ibrahim Hanna | [101] |
| by 1998 | Skepi Creole Dutch | Dutch-based creole | Guyana | | [102] |
| 1997–98 | Ngarnka | Pama-Nyungan | Australia | | |
| after 1997 | Aribwatsa | Austronesian | Papua New Guinea | Butoawê [103] | [104] |
| January 1997 | Sireniki Yupik | Eskimo–Aleut | Chukotka Peninsula, Russia | Valentina Wye | [105] |
| 1997 | Guazacapán Xinca | Xincan | Santa Rosa, Guatemala | | 1 semispeaker |
| 1997 | Jumaytepeque Xinca | Xincan | By Volcán Jumaytepeque, Guatemala | | |
| after 1996 | Hibito | Hibito–Cholon | Bobonaje River Valley | Natividad Grández del Castillo | [106] There were 500 speakers in 1850. |
| c. 1996 (?) | Malaryan | Dravidian | Kerala and Tamil Nadu, India | | [107] |
| 16 December 1996 | Chiwere | Siouan | Oklahoma and Kansas, United States | Truman Washington Dailey | [108] |
| by 1996 | Chiquimulilla Xinca | Xincan | Chiquimulilla, Guatemala | | The last semi-speaker Julian de la Cruz died in 1996. |
| by 1996 | Katabaga | Austronesian | Philippines | | [109] |
| by 1996 | Palumata | Austronesian? | Maluku, Indonesia | | [110] |
| by 1996 | Seru | Austronesian | Sarawak, Malaysia | | [111] |
| 5 November 1995 | Kasabe | Niger–Congo | Cameroon | Bogon | [112] |
| 6 August 1995 | Martuthunira | Pama-Nyungan | Western Australia | Algy Paterson | [113] |
| 8 January 1995 | Northern Pomo | Pomoan | California, United States | Edna Campbell Guerrero | |
| by 1995 | Mandawaca | Arawakan | Venezuela, Brazil | | [114] |
| late 1990s | Munichi | Isolate | Loreto Region, Peru | Victoria Huancho Icahuate | |
| after 1994 | Lachoudisch | Indo-European | Schopfloch, Bavaria | | [115] |
| 16 May 1994 | Luiseño | Uto-Aztecan | Southern California | Villiana Calac Hyde | A revitalization process is happening. |
| 30 April 1994 | Sakhalin Ainu | Ainu languages | Japan | Take Asai | [116] |
| 13 July 1993 | Eastern Abnaki | Algic | Maine, United States | Madeline Shay | [117] [118] |
| 1993 | Cholón | Hibito–Cholon | Huallaga River valley, Peru | | A few semispeakers remain. [119] |
| 7 October 1992 | Ubykh | Northwest Caucasian | Balıkesir Province, Turkey | Tevfik Esenç | [120] |
| 23 February 1991 | Roncalese (Erronkariko) dialect of Basque | Isolate | Spain | Fidela Bernat | [121] |
| 1991 | Ullatan | Dravidian | India | | [122] |
| 30 July 1990 | Wappo | Yuki–Wappo | California, United States | Laura Fish Somersal | [123] |
| early 1990s | Hermit | Austronesian | Manus Province, Papua New Guinea | | It has been mostly replaced by Seimat. |
| c. 1990s | Inku | Indo-European | Afghanistan | | [124] |
| c. 1990s | Lumaete dialect of Kayeli | Austronesian | central Maluku, Indonesia | | [125] |
| 1990s | Taman | Sino-Tibetan | Myanmar | | [126] |
| c. 1990s | Unggumi | Worrorra | Australia | Morndi Munro | [127] |
| 1990s? | Berti | Saharan | Dafur and Kordofan, Sudan | | |
| 20 September 1989 | Kamas | Uralic | Sayan Mountains, Soviet Union | Klavdiya Plotnikova | |
| March 1989 | Leliali dialect of Kayeli | Austronesian | central Maluku, Indonesia | | [125] [65] |
| after 1989 | Hukumina | Austronesian | Maluku, Indonesia | | [128] |
| 1989 | Miami-Illinois | Algic | along the Mississippi River, United States | | at least 500 users in 2016 [129] |
| 1989 | Kungarakany | Gunwinyguan | Northern Territory, Australia | Madeline England | [65] [130] |
| 16 September 1988 | Atsugewi | Palaihnihan | California, United States | Medie Webster | [131] |
| 1988 | ǁXegwi | Tuu | South Africa | Jopi Mabinda | [132] |
| 1980s | Bidyara | Pama-Nyungan | Queensland, Australia | | [133] |
| c. 1987 | Laua | Trans-New Guinea | Papua New Guinea | | |
| 4 February 1987 | Cupeño | Uto-Aztecan | California, United States | Roscinda Nolásquez | [134] |
| 1987 | Dyangadi | Pama-Nyungan | New South Wales, Australia | | [135] 137 speakers in 2021 census. [136] |
| 1987 | Negerhollands | Dutch-based creole | U.S. Virgin Islands | Alice Stevens | |
| by 1987 | Basa-Gumna | Niger-Congo | Niger State/Plateau State, Nigeria | | [137] |
| by 1987 | Yugambal | Pama-Nyungan | Queensland, Australia | | [138] |
| after 1986 | Bikya | Niger-Congo | Cameroon | | |
| after 1986 | Bishuo | Niger-Congo | Cameroon | | |
| April 1986 | Jiwarli dialect, Mantharta | Pama-Nyungan | Australia | Jack Butler | [139] |
| 1986 | Mangala | Pama-Nyungan | Western Australia | | [140] |
| 1986 | Volow | Austronesian | Vanuatu | Wanhan | [141] |
| late 1980s to early 1990s | Cahuarano | Zaparoan | Along the Nanay River in Peru. | | |
| 18 March 1984 | Deeside dialect, Scottish Gaelic | Indo-European | Scotland | Jean Bain | [142] |
| 1984 | Yavitero | Arawakan | Venezuela | | [65] [143] |
| February 1983 | Antrim Irish | Indo-European | Ireland | Séamus Bhriain Mac Amhlaig | [144] [145] |
| c. 1983 | Yangman | Australian (Wardaman isolate) | Northern Territory, Australia | | [146] |
| after 1982 | Tutelo | Siouan | Virginia, United States | Albert Green | |
| June 1982 | Kansa | Siouan | Oklahoma, United States | Ralph Pepper | |
| 1982 | Bala | Tungusic | Zhangguangcai Range | | [147] |
| 1982 | Dagoman | Australian | Northern Territory, Australia | Martha Hart | [148] |
| by 1982 | Dyugun | Australian | Western Australia | | [149] |
| by 1982 | Kato | Na-Dene | California, United States | | [150] |
| after 1981 | Dirari | Pama-Nyungan | South Australia | | [151] |
| after 1981 | Dyaberdyaber | Pama-Nyungan | Western Australia | | [152] [153] |
| after 1981 | Erre | Australian | Northern Territory, Australia | | [154] |
| after 1981 | Yawarawarga | Pama-Nyungan | Queensland and South Australia | | [155] |
| c. 1981 | Ternateño | Portuguese Creole | Maluku, Indonesia | | [156] |
| 1 May 1981 | Pitta Pitta | Pama-Nyungan | Queensland, Australia | | with the deaths of Ivy Nardoo of Boulia [157] |
| 1981 | Nagarchal | Dravidian? | India | | unattested |
| 1981 | Warrungu | Pama-Nyungan | Queensland, Australia | Alf Palmer | [158] [159] |
| by 1981 | Bina | Austronesian | Central Province (Papua New Guinea) | | |
| 1980 | Twana | Salishan | Washington, United States | | [65] [160] |
| 1980 | Yalarnnga | Pama-Nyungan | Australia | | |
| early 1980s | Muruwari | Pama-Nyungan | Queensland and New South Wales, Australia | | [161] |
| 1980s | Alchuka | Tungusic | Heilongjiang | | |
| 1980s | Kyakala (China) | Tungusic | Northeastern China | | |
| late 1970s - 1980s | Flinders Island | Pama-Nyungan | Australia | Johnny Flinders | [158] [153] |
| 1971 – 1981 | Kwadi | Khoe | southwestern Angola | | [162] |
| 1970s – 1980s | Chicomuceltec | Mayan | Mexico; Guatemala | | |
| 22 February 1979 | Barranbinja | Pama-Nyungan | New South Wales, Australia | Emily Margaret Horneville | |
| 1978 | Shasta | Shastan | California, United States | Clara Wicks | [163] |
| 3 November 1977 | Shuadit | Indo-European | southern France | Armand Lunel | [65] [164] |
| 24 August 1977 | Ngawun | Pama-Nyungan | Queensland, Australia | Cherry O'Keefe | [165] |
| 13 July 1977 | Nooksack | Salishan | Washington, United States | Sindick Jimmy | [65] |
| 1977 | Arran Gaelic | Indo-European | Isle of Arran | Donald Craig | [166] |
| by 1977 | Babuza | Austronesian | Taiwan | | [167] |
| by 1977 | Luilang | Austronesian | Banqiao District | | [167] |
| 1976–1999 | Kw'adza | Afroasiatic | Tanzania | | [168] |
| after 1976 | Muskum | Afroasiatic | western Chad | | [169] |
| before 1975 | Homa | Niger-Congo | southern Sudan | | [170] |
| 27 December 1974 | Manx | Indo-European | Isle of Man, British islands | Ned Maddrell | Now being revived as a second language [171] |
| 28 May 1974 | Selkʼnam | Chon | Tierra del Fuego, Argentina | Ángela Loij [notes 4] | |
| 1974 | Moksela | Austronesian | Maluku, Indonesia | | [172] |
| by 1974 | Cacaopera | Misumalpan | El Salvador | | [173] |
| after 1973 | Môa Remo | Panoan | Along the Môa River of Amazonas, Peru | | A word list was recorded in 1973. |
| by 1974 | Dicamay Agta | Austronesian | Luzon, Philippines | | The Dicamay Agta were killed by Ilokano homesteaders sometime between 1957 and 1974. |
| 9 October 1972 | Tillamook | Salishan | Oregon, United States | Minnie Scovell | [65] |
| 5 February 1972 | Hanis | Coosan | Oregon, United States | Martha Harney Johnson | [174] |
| 1972 | Mbabaram | Pama-Nyungan | Queensland, Australia | Albert Bennett | [175] |
| 1972 | Wyandot | Iroquoian | Oklahoma, United States; Quebec, Canada | | |
| by 1972 | Yugh | Yeniseian | central Siberia, Soviet Union | | [65] [176] |
| c. 1970s | Cocoliche | Italian-based pidgin | Buenos Aires, Argentina | | Some content survived in the lunfardo slang of Rioplatense Spanish dialect |
| 1970s | Damin | Constructed | Mornington Island | | |
| 1970s | Lelak | Austronesian | Sarawak, Malaysia | | [177] |
| late 20th century (?) | Nganyaywana | Pama-Nyungan | Australia | | |
| late 20th century (?) | Ngamini | Pama-Nyungan | South Australia | | |
| late 20th century (?) | Nila | Austronesian | Nila Island, Indonesia | | Speakers were relocated to Seram due to volcanic activity on Nila [178] |
| late 20th century (?) | Serua | Austronesian | Mount Serua, Indonesia | | Speakers were relocated to Seram due to volcanic activity on Serua [178] |
| late 20th century | Madhi Madhi | Pama–Nyungan | New South Wales, Australia | Jack Long | [179] |
| late 20th century | Newfoundland Irish | Indo-European | Newfoundland, Canada | | [180] |
| late 20th century | Soyot | Turkic | Buryatia, Khövsgöl Province | | Partly revitalized |
| late 20th century | Saraveca | Arawakan | Eastern lowlands Bolivia | | |
| 1968 | Welsh-Romani | Romani | Wales, United Kingdom | Manfri Wood | [181] |
| by 1968 | Sened | Afroasiatic | Tunisia | | |
| after 1965 | Barngarla | Pama-Nyungan | southern Australia | Moonie Davis | [182] |
| after 1965 | Napeca | Chapacuran | Bolivia | | Semispeakers remain. [183] |
| 24 July 1965 | Barbareño | Chumashan | California, United States | Mary Yee [notes 5] | [184] |
| 1965 | Ineseño | Chumashan | California, United States | | [185] |
| 1965 | Wakawaka | Pama-Nyungan | Queensland, Australia | | [186] |
| c. 1964 | Aariya? | spurious? | India | | [187] |
| after 1964 | Paratio | Xukuruan? | Pesqueira, Pernambuco, Brazil | | It was spoken by a few people in Pesqueira in 1964. |
| after 1964 | Sapará | Cariban | South America | | Loukotka (1968) |
| after 1964 | Tocantins Apiaká | Cariban | South America | |
| after 1964 | Kustenau | Arawakan | Mato Grosso, Brazil | |
| after 1964 | Kunza | unclassified (isolate?) | Atacama Desert, Chile/Peru | |
| 10 August 1963 | Galice | Na-Dene | Oregon, United States | Hoxie Simmons | |
| 10 January 1963 | Upper Umpqua | Na-Dene | Oregon, United States | Wolverton Orton | |
| 1963 | Jorá | Tupi | Bolivia | | [65] |
| 1962 | Wiyot | Algic | California, United States | Delia Prince | [188] |
| 1961 | Northeastern Pomo | Pomoan (Hokan?) | California, United States | | |
| by 1961 | Xocó | unclassified | Sergipe, Alagoas, Brazil | | Only a few people remembered the language in 1961. It is not clear if this is a single language. |
| by 1961 | Pankararú | unclassified | Pernambuco, Alagoas, Brazil | | Only two people remembered the language in 1961. |
| 1960 | Oriel dialect of Irish | Indo-European | Ireland | Annie O'Hanlon | [189] |
| 1960 | Siuslaw | Isolate | Oregon, United States | Mary Barrett Elliott | Last speaker of Lower Umpqua dialect was Billy Dick, who died in 1957. [174] |
| 1960 | Gününa Küne | Chon | Argentina | | |
| 1960s | Cuitlatec | Isolate | Guerrero, Mexico | Juana Can | [190] |
| 1960s | Luren | Sino-Tibetan | Guizhou | | |
| 1960s | Timor Pidgin | Portuguese creole | East Timor | | [191] |
| 16 April 1959 | Catawba | Siouan | South Carolina, United States | Chief Sam Blue | [192] |
| 22 September 1958 | Molala | Isolate | Oregon, United States | Fred Yelkes | [174] |
| 1958 | Salinan | Isolate (Hokan?) | California, United States | | |
| 25 March 1957 | Natchez | Isolate | Mississippi, United States | Nancy Raven | [193] [194] The Natchez people are attempting to revive this language. [195] |
| by 1956 | Palmela | Cariban | South America | | [196] |
| 1952–1956 | Aasáx | Afroasiatic | Tanzania | | [197] |
| after 1954 | Tây Bồi | French-based Pidgin | Vietnam | | [198] [199] |
| 1954 | Central Kalapuya | Kalapuyan | Oregon, United States | John B. Hudson | [174] |
| 1954 | Ifo | Austronesian | Erromanga Island, Vanuatu | James Nalig | [200] |
| 1952 | Martha's Vineyard Sign Language | Sign language | Massachusetts, United States | Katie West | |
| 1951 | Alsea dialect | Isolate (Alsean) | Oregon, United States | John Albert | [174] |
| by 1951 | Xukuru | Xukuruan | Pernambuco and Paraíba, Brazil | | Known from a wordlist and sketch from Geraldo Lapenda (1962). Only rememberers remained by 1951. |
| c. 1950 | Bohemian Romani | mixed language | Czechoslovakia, Central Europe | | after World War II, due to extermination of most of its speakers in Nazi concentration camps. |
| 1950 | Kaniet | Austronesian | Manus Province, Papua New Guinea | | [65] [201] |
| c. 1950s | Makuva | Trans–New Guinea? | East Timor | | [59] |
| c. 1950s | Kilit | Indo-European | Nakhchivan | | [202] |
| c. 1950s | Pijao | unclassified (Cariban?) | Tolima Department, Colombia | | [203] |
| 1950s | Kepkiriwát | Tupian | Rondônia, Brazil | | |
| by 1950s | Mikira | Cahuapanan | Loreto, Peru | | A word list was made by Enrique Stanko Vráz and published in 1949. |
| mid-20th century | Ventureño | Chumashan | California, United States | | |
| mid-20th century | Basay | Austronesian | Taiwan | | |
| mid-20th century | Slovincian | Indo-European | Pomerania, Poland | | |
| mid-20th century | Southern Pame | Oto-Manguean | Southern Mexico | | |
| mid-20th century | Tequiraca | Isolate | Loreto, Peru | | 2 people remembered the language in 2008. [204] |
| mid-20th century | Sensi | Panoan | right bank of Ucayali River, Peru | | A word list was created by Günter Tessmann in 1930. [205] |
| around mid-20th century | Tubar | Uto-Aztecan | Northern Mexico | | |
| around mid-20th century? | Chico | Maiduan | Central California | | |
| 6 December 1948 | Tunica | Isolate | Louisiana, United States | Sesostrie Youchigant | [206] |
| after 1947 | Gafat | Afroasiatic | along the Abbay River, Ethiopia | | [207] |
| after 1944 | Opón-Carare | Cariban | Colombia | | [208] |
| 1943 | Payagua | Isolate (Mataco–Guaicuru?) | Alto Paraguay, Paraguay | María Dominga Miranda | [209] |
| 3 March 1940 | Pentlatch | Salishan | Vancouver Island, Canada | Joe Nimnim | [65] Being revived [210] [211] |
| 28 January 1940 | Chitimacha | Isolate | Louisiana, United States | Delphine Ducloux | [212] |
| c. 1940 | Eudeve | Uto-Aztecan | Sonora, Mexico | | |
| c. 1940s | Chemakum | Chimakuan | Washington, United States | | |
| c. 1940s | Ossory dialect of Irish | Indo-European | County Kilkenny, Ireland | | |
| c. 1940s | Kitanemuk | Uto-Aztecan | California, United States | Marcelino Rivera, Isabella Gonzales, or Refugia Duran | |
| c. 1940s | Northern Manx dialect of Manx | Indo-European | Isle of Man | | [213] |
| 1940s | Tongva | Uto-Aztecan | Southern California, United States | | being revived |
| 22 May 1939 | Rumsen | Utian | California, United States | Isabel Meadows | [214] |
| 9 May 1939 | Miluk | Coosan | Oregon, United States | Annie Miner Peterson | [215] |
| 16 January 1937 | Northern Kalapuya | Kalapuyan | Oregon, United States | Louis Kenoyer | |
| 1937 | Yoncalla | Kalapuyan | Oregon, United States | Laura Blackery Albertson | [216] |
| after 1936 | Yarumá | Cariban | South America | | |
| 1936 | Narungga | Pama-Nyungan | South Australia, Australia | | [217] |
| 8 January 1935 | Biloxi | Siouan | Louisiana, United States | Emma Jackson | [218] |
| 1934 | Juaneño | Uto-Aztecan | California, United States | | |
| 1934 | Chochenyo | Utian | California, United States | José Guzmán | [219] |
| 1934 | Takelma | Isolate | Oregon, United States | Frances Johnson | [220] |
| 1933 | Gabrielino | Uto-Aztecan | California, United States | | |
| after 1932 | Pauxiana | Cariban | Roraima, Brazil | | |
| 1931–1951 | Akarbale | Andamanese | Andaman Islands, India | | [221] |
| 1931–1951 | Akakede | Andamanese | Andaman Islands, India | | [221] |
| 1931–1951 | Opucikwar | Andamanese | Andaman Islands, India | | [221] |
| after 1931 | Tonkawa | Isolate | Oklahoma/Texas/New Mexico, United States | | |
| after 1931 | Jaquirana Remo | Panoan | Amazonas, Brazil | | A word list was made in 1931. |
| after 1931 | Tuxinawa | Panoan | Acre, Brazil | | A word list was made in 1931. |
| by 1931 | Aka-Bea | Andamanese | Andaman Islands, India | | [221] |
| by 1931 | Okojuwoi | Andamanese | Andaman Islands, India | | [221] |
| after 1930 | Morique | Arawakan | Between the Ucayali River and Javari River | | |
| c. 1930 | Mattole | Na-Dene | California, United States | | |
| 29 January 1930 | Mutsun | Utian | California, United States | Ascencion Solorsano | |
| 1930s | Pirlatapa | Pama-Nyungan | South Australia | Blanche Tom | The last rememberer, Fred Johnson, died in 1967. [222] |
| c. 1930s | Cayuse | unclassified | Oregon, United States | | |
| c. 1930s | Kathlamet | Chinookan | Washington/Oregon, United States | Charles Cultee | [174] |
| c. 1930s | Lower Chinook | Chinookan | Washington/Oregon, United States | | |
| c. 1930s | Mahican | Algic | New York, United States | | |
| c. 1930s | Clackamas dialect of Upper Chinook | Chinookan | Washington/Oregon, United States | | |
| c. 1930s | Kitsai | Caddoan | Oklahoma, United States | Kai Kai | [223] |
| c. 1930s | Tapachultec | Mixe–Zoque | Southern Mexico | | |
| by 1930 | Opata | Uto-Aztecan | Northern Mexico | | |
| between 1920 and 1940 | Ajawa | Afroasiatic | Bauchi State, Nigeria | | [224] |
| 25 December 1929 | Kaurna | Pama-Nyungan | South Australia | Ivaritji | [225] now being revived |
| c. 1929 | Bear River dialect of Mattole | Na-Dene | California, US | | |
| 1928 | Ottoman Turkish | Turkic | Turkey | | Evolved into Turkish in 1928. |
| c. 1928 | Anauyá | Arawakan | Castaño Viejo River Amazonas, Venezuela | | Only documentation was published in 1928. |
| after 1927 | Teshenawa | Afroasiatic | Jigawa State, Nigeria | | [226] |
| after 1927 | Tarauacá Kashinawa | Panoan | Amazonas, Brazil | | A word list was made in 1927. |
| after 1927 | Blanco River Remo | Panoan | Loreto Province, Peru | |
| after 1927 | Urupá | Chapacuran | Brazil | |
| after 1927 | Yarú | Chapacuran | Brazil | |
| after 1927 | Karipuna (Jau-Navo) | Panoan | Brazil | |
| 1927 | Tsetsaut | Na-Dene | British Columbia, Canada | | [227] |
| after 1925 | Subtiaba | Oto-Manguean (Subtiaba-Tlapanec) | Nicaragua | | |
| 1925 | Papuan Pidgin English | English-based pidgin | British New Guinea | | [228] |
| 1925 | Vanji | Indo-European | Emirate of Bukhara | | [229] |
| after 1924 | Auyokawa | Afro-Asiatic | Jigawa State | | |
| January 1922 | Chimariko | Isolate | California, United States | Sally Noble | [230] [231] |
| after 1921 | Chagatai | Turkic | Central Asia including Turkmenistan | | Chagtai is still studied in Uzbekistan and Turkey. [232] |
| 30 June 1921 | Tataviam | Uto-Aztecan | California, United States | Juan José Fustero | |
| by 1921 | Okol | Andamanese | Andaman Islands, India | | [233] |
| after 1920s | Sarghulami | Indo-European | Badakhshan | | May be spurious [234] |
| after 1920 | Sinacantán Xinca | Xincan | Santa Rosa, Guatemala | | A word list was recorded by Walter Lehmann in 1920. |
| c. 1920 | Mochica | Isolate | northwest Peru | | |
| c. 1920s | Fergana Kipchak | Turkic | Fergana Valley | | [235] |
| c. 1920s | Otuke | Bororoan | Mato Grosso, Santa Cruz | | |
| 1920s | Pataxó Hã-Ha-Hãe | Macro-Jê | Brazil | | [236] fully in 1992 with the death of Bahetá. [237] [238] Being revived |
| by 1920 | Yupiltepeque Xinca | Xincan | Guatemala | | [239] |
| c. 1918 | Island Carib | Cariban | Lesser Antilles, Caribbean Sea | Ma Gustave | [240] An offshoot survives as Garifuna. |
| after 1917 | Pochutec | Uto-Aztecan | Oaxaca, Mexico | | |
| 15 June 1917 | Obispeño | Chumashan | Southern California, United States | Rosario Cooper | [241] |
| 25 March 1916 | Yahi | Isolate (Hokan?) | California, United States | Ishi [notes 6] | [242] |
| after 1915 | Chiapanec | Oto-Manguean | Chiapas, Mexico | | There were only 3 speakers in 1915. [243] |
| 1915 | Yamhill dialect of Northern Kalapuya | Kalapuyan | Oregon, United States | | |
| 1910s | ǀXam | Tuu | South Africa | | |
| c. 1910s | Kwalhioqua-Clatskanie | Na-Dene | Washington, United States | | [244] |
| after 1908 | Siraya | Austronesian | southwestern Taiwan | | [245] being revived |
| 18 July 1908 | Mohegan-Pequot | Algic | southern New England, United States | Fidelia Fielding | [246] |
| after 1906 | Arazaire | Panoan | Cusco Province, Peru | | A word list was recorded in 1906. |
| 24 February 1905 | Flinders Island lingua franca (Tasmanian) | unclassified | Tasmania, Australia | Fanny Cochrane Smith [notes 7] | [247] [248] |
| after 1904 | Atsawaka | Panoan | Puno Province, Peru | | There were 20 speakers in 1904. |
| after 1902 | Dyirringany | Pama–Nyungan | New South Wales, Australia | | |
| between 1900 and 1920 | Russian Kyakala dialect of Udege language | Tungusic | Russia | | [249] |
| between 1900 and 1920 | Jangil | Ongan | Andaman Islands, India | | [250] |
| c. 1900 | Henniker Sign Language | Village sign | New Hampshire, United States | | |
| c. 1900 | Moran | Sino-Tibetan | Assam, India | | [251] |
| May 1900 | Moriori | Austronesian | Chatham Island, New Zealand | Hirawanu Tapu [252] | |
| 1900 | Wulguru | Pama-Nyungan | Australia | | |
| by 1900 | Classical Mandaic | Afroasiatic | Iran; Iraq | | [253] |
| by 1900 | Piro Pueblo | Tanoan | New Mexico, United States | | |
| 1900s | Iazychie | Indo-European | Halychyna, Bukovina, Zakarpattia | | [254] |
| 1900s | Judeo-Venetian | Indo-European | Venice | | [255] |
| 1900s | Rotvælsk | Indo-European | Denmark | | [256] |
| early 20th century | Atakapa | Isolate | Louisiana/Texas, United States | | |
| early 20th century | Nari-Nari | Pama–Nyungan | New South Wales, Australia | Angus Myers [257] | |
| early 20th century | Kamakã | Macro-Jê | Bahia, Brazil | | A few words of Kamakã have been preserved to the modern day. [258] |
| early 20th century | Jersey Dutch | Dutch-based creole | New Jersey, United States | | |
| early 20th century | Kazukuru | Austronesian | New Georgia, Solomon Islands | | |
| early 20th century | Kyakhta Russian–Chinese Pidgin | Chinese/Russian-based contact language | | | |
| early 20th century | Chaná | Charruan | Uruguay | | |
| early 20th century | Marawán | Arawakan | Brazil | | |
| early 20th century | East Leinster dialect, Irish | Indo-European | Ireland | | [259] |
| early 20th century | Ingain | Macro-Jê | Santa Catarina, Brazil | | |
| beginning of 20th century | Rangas | Sino-Tibetan | Uttarakhand | | [260] |