The Salish peoples are indigenous peoples of the American and Canadian Pacific Northwest, identified by their use of the Salish languages which diversified out of Proto-Salish between 3,000 and 6,000 years ago. The term "Salish" originated in the modern era as an exonym created for linguistic research. Salish is an anglicization of Séliš, the endonym for the Salish Tribes of the Flathead Reservation. The Séliš were the easternmost Salish people and the first to have a diplomatic relationship with the United States so their name was applied broadly to all peoples speaking a related language. Salishan languages The Salish (or Salishan) people are in four major groups: Bella Coola (Nuxalk), Coast Salish, Interior Salish, and Tsamosan, who each speak one of the Salishan languages. The Tsamosan group is usually considered a subset of the broader Coast Salish peoples. Among the four major groups of the Salish people, there are twenty-three documented languages. At least five of these are no longer in use, while the rest are seriously endangered. The majority of fluent Salish-speakers are elderly, and younger speakers are quite rare. In spite of this, there are ongoing efforts to keep the languages alive through revitalization programs planned and conducted by various tribal organisations. Currently, a team of scholars is conducting research on the languages in order to create reference material and educational resources. Salish languages, especially those of the Coast peoples, are threatened primarily by assimilation. State programs such as the Canadian residential schools (where indigenous languages were prohibited) have been a major factor in reducing the number of fluent Salish speakers. Schools today, however, from the secondary to the university level, are actively promoting knowledge and use of the Salish languages. In 1988, the Self Governance Demonstration Project of the Confederated Salish and Kootenai Tribes (the CSKT) was successful, and the U.S. government returned full autonomy to their tribal leadership in 1993.