The Sumerians created the first civilization in southern Mesopotamia. They spoke a language not closely connected to other languages. Not surprisingly, there have therefore been many (sometimes patriotically influenced) theories regarding the origin of the Sumerians ("The Sumerian Question"). Claims have ranged from an indigenous people (not necessarily the same as the current inhabitants) to immigrants/conquerors (or an immigrant/conqueror ruling elite), sometimes claimed to have originated in very distant lands.
The Sumerian civilization was influenced by the earlier Samarra culture. The Samarra people may have spoken an Indo-European language (sometimes termed "Euphratic") that influenced the Sumerian language.
What, then, is certain and what possible about the taxonomic position of the Sumerians and the founders of the Indus Valley civilization? Certainly there is no evidence of any Mongolid or Negrid element in these Europid people, nor were they Armenids (though members of the latter taxon played a large part in the later development of civilization in Babylonia). The people who originated the civilization in Sumeria and the Indus Valley may have been Mediterranid, or may have belonged to the somewhat similar Capellid taxon, or may indeed have belonged to both, and may have included hybrids between the two.—Race, John R Baker, Oxford University Press, 1974
- The case for Euphratic
- Sumerian and Indo-European: a surprising connection
- In search of the genetic footprints of Sumerians
- Physical anthropology and the “Sumerian problem”
- Sumerian and Indo-European: a surprising connection https://new-indology.blogspot.nl/2015/05/sumerian-and-indo-european-surprising.html