Cayuse

Cayuse was the language of the Cayuse people of what is now northeastern Oregon in the United States, and is classified as a language isolate with no established relatives. The earliest written record of its vocabulary was compiled by Horatio Hale in 1846 during the United States Exploring Expedition, and further material was later gathered by linguists including Edward Sapir and Bruce Rigsby. By the time serious documentation began, most remaining Cayuse speakers were more fluent in neighboring languages such as Sahaptin or Nez Perce, and the language became extinct in the 1930s; comparisons with other Pacific Northwest languages have found too few similarities to establish any confirmed family relationship.