According to the language family tree classification by Ethnologue, Okpe, Urhobo and Uvwie, alongside Eruwa and Isoko, make up the five Southwestern Edoid languages of the Benue-Congo group. Quoting Johnstone (1993), Ethnologue puts the population of Urhobo people at 546,000, Okpe 25,400 (2000) and Uvwie 19,800 (2000). These three languages have geographically neighbouring languages: Izon and Itsekiri to the west and south, Ukwuani and Isoko to the east and Edo to the north. Thus, Isoko and Urhobo are similar languages that belong to the same linguistic family.
There is literature for both the Urhobo and Isoko languages. There are Bibles and Christian hymn books for both languages. There are also dictionaries for Urhobo, written by Ukere, Osubele, Juliua Arerierian and Akpobome Diffre-Odiete. While all the former ones are bilingual, the last one by Diffre-Odiete is a multilingual dictionary of English, Okpe, Urhobo and Uvwie, with over 900 entries in the four languages.
Okpe (ISO 639 – 3:oke), Urhobo (ISO 639 – 3:urh) and Uvwie (ISO 639 – 3:evh) are three diverse languages spoken in an area belonging to one and the same ethnic group called the Urhobo people of Delta State in southern Nigeria, Africa. The Urhobo ethnic nation is culturally united, but it comprises twenty-four political clans or kingdoms. Okpe is spoken in only one kingdom (the largest in Urhoboland). Uvwie is spoken in two kingdoms, while Urhobo is spoken, with dialectical varieties, in the remaining twenty-one kingdoms. The Agbarho dialect is the accepted standard of written Urhobo for all twenty-four kingdoms. The Okpe and Uvwie clans view their languages as distinct languages and not as dialects of Urhobo. However, in their communication with people of other Urhobo clans, they use Urhobo, English or Nigerian Pidgin.