the smallest branch of the Niger-Congo language family (Niger-Congo languages). It consists of a language cluster, Ijo (Ijaw), comprising seven other language clusters with a total of approximately two million speakers, and Defaka (Afakani), a solitary language spoken by very few. All these languages are found in the relatively narrow coastal Niger River delta region of Nigeria. The Ijo language cluster includes the languages of the Eastern Ijo, namely Kalabari, Okrika, and Ibani; the Brass Ijo, including Nembe and Akassa; Izon, including Bumo, Kolokuma, Mein, and Arogbo; Biseni; Okodia; Oruma; and Nkoroo.

The Ijo were among the first West Africans to come into contact with Europeans; thus the Ijo language is believed to be one of the first Nigerian languages written. As a result of the slave trade, the Kalabari language was transplanted to eastern Guyana, where it was spoken for decades and later became the basis of a Dutch creole, Berbice, now nearly extinct.