The Isoko language is spoken by the Isoko people in the Niger Delta of Southern Nigeria; specifically in regions of Delta and Bayelsa States. The Isoko and Urhobo languages are essentially dialects of the same language. However, the source dialect is a matter of dispute. Nevertheless, both dialects are derivatives of the Edoid language group.
Michael A. Marioghae, working with Peter Ladefoged in 1962, made one of a few audio recordings of sample Isoko words that are made available at the UCLA phonetics archive.