The following 18 languages were last known to have one remaining speaker. They are the most at-risk languages on a list of 199 classified in the United Nations Atlas of Endangered Languages as critically endangered, meaning they have fewer than 10 documented speakers.
Regions with the most linguistic diversity also tend to have the most endangered languages.
1. Apiaka is spoken by the indigenous people of the same name who live in the northern state of Mato Grosso in Brazil. The critically endangered language belongs to the Tupi language family. As of 2007, there was one remaining speaker.
2. Bikya is spoken in the North-West Region of Cameroon, in western Africa. The last record of a speaker was in 1986, meaning the language could now be extinct. This predicament resembles that of another Cameroon language, Bishuo, whose last recorded speaker was also in 1986.
4. Dampal is spoken in Indonesia, near Bangkir. Unesco reported that it had one speaker as of 2000.
5. Diahoi (also known as Jiahui, Jahoi, Djahui, Diahkoi, and Diarroi) is spoken in Brazil. Those who speak it live on the indigenous lands Diahui, Middle Madeira river, Southern Amazonas State, Municipality of Humaita. As of 2006, one speaker was left.
7. Laua is spoken in the Central Province of Papua New Guinea. It is part of the Mailuan language group and is nearly extinct, with one speaker documented in 2000.
10. Pemono is spoken in Venezuela and has one remaining speaker, who lives in an Upper Majagua village.
11. Taje is one of the endangered languages spoken in the country of Indonesia. As of 2000, there was one speaker remaining in Sulawesi.
12. Taushiro (also known as Pinche, or Tausiro in Spanish) is an isolated language spoken in Peru. The speakers, who were from the Loreto Province and Tigre River basin, married non-Taushiro speakers and adopted Spanish or other languages. There was one speaker documented in 2008.
13. Tinigua is a nearly extinct language from Colombia. While originally from the Yari River, most of descendants now live in the Sierra de la Macarena and do not speak the language any more. As of 2008, the last speaker lived near the Guayabero River.
14. Tolowa, the language of the Tolowa Native American tribe, is spoken by a few members located in the Smith River Rancheria. a sovereign nation, near Crescent City, Calif. Tolowa is part of the Athabaskan language family. One speaker remained as of 2008.
16. Wintu-Nomlaki is spoken by the Wintu tribe in California. The language has two dialects: Nomlaki, which is spoken along the Sacramento River south of Red Bluff, and the other is Wintu. As of 2008, there was one fluent speaker and several speakers with moderate command of the language.
17. Yaghan is spoken in Chile, in the community of Villa Ukika on Navarino Island, located in the Magallanes Territory. As of 2005, the last remaining speaker and pureblood member of the Yaghan tribe was an elderly woman named Cristina Calderon.
18. Yarawi (or Suena) is spoken is Papua New Guinea, near Morobe town in Morobe Province. One speaker was documented in 2000.
Sources: UNESCO Interactive Atlas of the World’s Languages in Danger and the Encyclopedia of the World’s Endangered Languages by Christopher Moseley.