Caddo is the only surviving Southern Caddoan language of the Caddo language family. It is spoken by the Caddo Nation of Oklahoma. Today, only 25 elderly speakers are estimated to remain, none of whom are monolingual Caddo speakers, making Caddo a critically endangered language. There are several mutually intelligible dialects of Caddo; some of the more prominent dialects include Kadohadacho, Hasinai, Hainai, Natchitoches, and Yatasi. Today, the most commonly used dialects are Hasinai and Hainai.

Caddo is linguistically related to the members of the Northern Caddoan language family; these include the Pawnee-Kitsai (Keechi) languages (Arikara, Kitsai, and Pawnee) and the Wichita language. Kitsai is now extinct, and Pawnee, Arikara, and Wichita each have fewer surviving speakers than Caddo does. Another language, Adai, is postulated to have been a Caddoan language while it was extant, but because of scarce resources and the language’s extinct status, this connection is not conclusive, and Adai is generally considered a language isolate.

The Caddo Nation is a confederacy of several Southeastern Native American tribes, who traditionally inhabited much of what is now East Texas, northern Louisiana and portions of southern Arkansas and Oklahoma. Today the Caddo Nation of Oklahoma is a single federally recognized tribe with its capital at Binger, Oklahoma. The different Caddo languages have converged into a single language.

The Caddo Nation was previously known as the Caddo Tribe of Oklahoma. A tribal constitution provides for a tribal council consisting of eight members with a chairperson, based in Binger, Oklahoma. The tribal complex, dance grounds, and the Caddo Heritage Museum are located south of Binger. 5757 people are enrolled in the tribe, with 3044 living within the state of Oklahoma. The tribe operates its own housing authority and issues its own tribal vehicle tags. It maintains administrative centers, dance grounds, several community centers, and an active NAGPRA office.

Several programs exist to invigorate Caddo traditions. The tribe sponsors a summer culture camp for children. The Hasinai Society and Caddo Culture Club both keep Caddo songs and dances alive, while the Kiwat Hasinay Foundation is dedicated to preserving the Caddo language.