No known L1 speakers. Last fluent speakers of Iowa and Oto died in 1996 (1997 J. GoodTracks). Ethnic population: 1,150 (Golla 2007).
Iowa (Baxoje, Ioway), Oto (Chiwere, Jiwele, Jiwere, Otoe), Niutaji (Missouri, Missouria, Nyut’chi).
In 1999, only 4 passive speakers remain, none fluent (Golla 2007).
Iowa and Oto formerly 1 language, with some family variations cross-cutting tribal affiliations. Missouri dialect extinct for many years. Language preservation activities taking place in Oklahoma.