The Cayuse language is an extinct language formerly spoken by the Cayuse

Cayuse

The Cayuse are a Native American tribe in the state of Oregon in the United States. The Cayuse tribe shares a reservation in northeastern Oregon with the Umatilla and the Walla Walla tribes as part of the Confederated Tribes of the Umatilla Indian Reservation...

 Native American tribe in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Oregon

Oregon

Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

. The Cayuse name for themselves was Liksiyu (see Aoki 1998).

The Cayuse language is unclassified. It has been proposed in the past that it may be related to Molala

Molala

The Molala were a people of the Plateau culture area in central Oregon, United States. Some consider them extinct, though they are one of the Confederated Tribes of the Grand Ronde Community of Oregon, with 141 of the 882 members in the 1950s claiming Molala descent.-Language:The Molalla language...

, making up a Waiilaptuan family ultimately related to the Penutian

Penutian languages

Penutian is a proposed grouping of language families that includes many Native American languages of western North America, predominantly spoken at one time in Washington, Oregon, and California. The existence of a Penutian stock or phylum has been the subject of debate among specialists. Even the...

stock. This proposal is currently unproven. The language has been extinct since the 19th century.