L1 users: 59 (2010 census), decreasing. Ethnic population: 220 (2000 census).
Louisiana: Koasati Reservation near Elton; Oregon; Texas: Alabama-Koasati Reservation near Livingston, others elsewhere.
More in Louisiana than Texas. Use decreased until the last decade. Fewer than 10 primary school-age speakers. Home, religious services. Mainly adults. Positive attitudes. A few also use Cajun French [frc], with more proficiency than in English. Also use Alabama [akz], Choctaw [cho], English [eng]. Used as L2 by Alabama [akz].
Latin script [Latn].