Proto-Euphratean was considered by some Assyriologists (for example Samuel Noah Kramer), to be the substratum language of the people that 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" (as in the fruit), also do not appear to have a Sumerian or Semitic 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.).
Another example are the "banana languages," which are attested by personal names used in Sumerian texts. These names have a characteristic feature, reduplication of syllables (like in the word banana): Inanna, Zababa, Chuwawa, Bunene etc. Such feature of the "banana languages" reminds the extinct Minoan language whose genetic relations are clear as same race. The hypothesis was proposed by Igor Dyakonov and Vladislav Ardzinba who identified these hypothetical languages with the Samarran culture.[1]