Proto-Euphratean is a hypothetical unclassified language or languages which was considered by some Assyriologists to be the substratum language of the people who introduced farming into Southern Iraq in the Early Ubaid period.
Literature
• fix • Vanseveren, Sylvia. "A "New" Ancient Indo-European Language? On Assumed Linguistic Contacts between Sumerian and Indo-European "Euphratic"". In: The Journal of Indo-European Studies (JIES). Vol. 36, Nº. 3-4 (FALL/WINTER), 2008: pp. 371-382. .