423,000 (Johnstone and Mandryk 2001).
Delta state: Ukwuani, Ethiope East, Ndokwa West, Ughelli North, Ughelli South, Isoko North, and Isoko South LGAs; Bayelsa state: Sagbama LGA; Edo state: Orhionmwon LGA.
Aviara, Elu, Emede, Enhwe, Ibiede, Imiv, Irri (Iri), Itebiege, Iwire (Igbide), Iyede, Iyede-Ami, Iyowo, Ofagbe, Ole (Oleh), Olomoro, Owe (Owhe), Oyede, Ozoro, Ume, Unogboko, Uti, Uzere.
Used as L2 by Eruwa [erh].
Latin script [Latn].
“Sobo” and “Igabo” are offensive names. “Biotu”, interior people, is the Izon name for the Isoko and is not meant offensively by the Izon; however, the Isoko do not like it.