Proto-Euphratean is a hypothetical unclassified language or languages which was considered by some Assyriologists (such as Samuel Noah Kramer) to be the substratum language of the people who introduced farming into Southern Iraq in the Early Ubaid period (5300–4700 BC).
Benno Landsberger and other Assyriologists argued that by examining the structure of Sumerian names of occupations, as well as toponyms and hydronyms, one can suggest that there was once an earlier group of people in the region who spoke an entirely different language, often referred to as Proto-Euphratean. Terms for "farmer", "smith", "carpenter", and "date" (the fruit) do not appear to have a Sumerian or Semitic origin.
Igor Dyakonov and Vladislav Ardzinba proposed a different term, "banana languages", based on a characteristic feature of multiple personal names attested in Sumerian texts, namely reduplication of syllables (as in the English word banana): Inanna, Zababa, Chuwawa/Humbaba, Bunene, Pazuzu, etc found in Sumerian, Akkadian, Assyrian and Babylonian texts. The same feature was attested in some other unclassified languages, including Minoan. The same feature is allegedly attested by several names of Hyksos rulers: although the Hyksos tribes were Semitic Canaanites, some of their names, like Bnon, Apophis, etc. were apparently non-Semitic in origin.
Rubio challenged the substratum hypothesis, arguing that there is evidence of borrowing from more than one language. This theory is now predominant in the field (Piotr Michalowski, Gerd Steiner, etc.).
A related proposal by Gordon Whittaker is that the language of the proto-literary texts from the Late Uruk period (c. 3350–3100 BC) is an early Indo-European language that he terms "Euphratic", although this does not have mainstream support.
- История древнего Востока, т.2. М. 1988. (in Russian: History of Ancient Orient, Vol. 2. Moscow 1988. Published by the Soviet Academy of Science), chapter III.
- История древнего Востока, т.2. М. 1988. (in Russian: History of Ancient Orient, Vol. 2. Moscow 1988. Published by the Soviet Academy of Science), p. 229.
- Whittaker, Gordon (2008). "The Case for Euphratic" (PDF). Bulletin of the Georgian National Academy of Sciences. Tbilisi. 2 (3): 156–168. Retrieved 11 December 2012.
- Rubio, Gonzalo (January 1999). "On the Alleged "Pre-Sumerian Substratum"". Journal of Cuneiform Studies. 51 (1): 1–16. doi:10.2307/1359726. JSTOR 1359726. S2CID 163985956.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. ISSN 0092-2323.