Sabine River Spanish is a variety of the Spanish language spoken on both sides of the Sabine River between Texas and Louisiana. It has been spoken by a few communities descended from the 18th-century colonists who established Los Adaes and Nacogdoches. Due to its historical origins, it has a mostly conservative phonology with a vocabulary derived from rural Mexican Spanish. It is facing language death as it has not been passed onto children for several generations.

Sabine River Spanish was formed from rural Mexican Spanish, in spite of the common belief in Nacogdoches that the Spanish-speaking group around the Sabine River is of Isleño origin. The Sabine River Spanish-speaking communities have no terms to identify themselves as a group. Adaeseño, in reference to Los Adaes, has been used by Armistead and Dr. Comfort Pratt for the dialect spoken on the Louisiana side of the river. Stark (1980) uses "Zwolle-Ebarb Spanish", from the names of two towns in Louisiana where it's spoken. Lipski uses the term Sabine River Spanish because the dialect extends to both sides of the river.

The Sabine River Spanish communities were founded as part of a Spanish effort to settle the eastern edge of Texas and adjoining areas of Louisiana in the 1700s. Nacogdoches was founded as part of this settlement and so was Los Adaes.

The Spanish language was preserved in the Sabine River communities until the 20th century due to isolation and, in Texas at least, ethnic solidarity. The Louisiana communities had less ethnic solidarity but greater social isolation due to their distance from population centers, poverty, racial differences from the surrounding population, and the fact they spoke a "foreign" language. The establishment of public schooling exerted strong linguistic pressure on these communities to learn and exclusively speak English, and the arrival of modern infrastructure such as electricity, paved roads, telephones, and the Kansas City Southern Railway through Zwolle reduced their isolation. This stopped the intergenerational transmission of Spanish, with most Spanish-speaking residents choosing not to teach their children the language. In this way the Spanish language has largely died out in a single generation along the Sabine River.

This dialect is currently moribund. As of the 1980s, there were no more than 50 individuals with significant active competence in Spanish on either side of the river. Stark (1980) estimated the presence of just ten people who still speak Spanish fluently in the Zwolle-Ebarb area, who were mainly in their seventies and eighties.

The Sabine River area's Spanish dialect is found on either side of the Toledo Bend Reservoir along the Sabine River. Most of the Spanish speakers in the Louisiana side were found around Zwolle, Ebarb and Noble, and in the Spanish Lake community near Robeline. In Texas they are concentrated in the Moral community west of Nacogdoches.

The Louisiana and Texas communities differ in terms of ethnic identification. Louisiana residents have diverse appearances, some being very pale and others vary dark-complexioned, and have experienced a re-surfacing of American Indian identity. As a result, they may identify ethnically as either Spanish, Indo-Spanish, or simply American Indian. The Louisiana residents have been called "Meskin", "Chonche", and "Red Bones" by their Anglo-American neighbors. Louisiana residents reject any identification as "Mexican", while Moral residents freely use the term mexicano and even occasionally call their dialect mexicano. In Moral there is no identification with Native American culture, despite the open acknowledgement of many trigueño, or 'dark-complexioned' residents.

Different studies and surveys have focused on different Spanish-speaking communities in the area. Stark (1980) focuses on the variety spoken in Zwolle and Ebarb; four of her five informants have lived most of their lives in Ebarb, with one later moving to Zwolle, while one lived most of his life near Zwolle. Pratt focused on all the Louisiana dialects, calling them Adaeseño.