Page "Assyria" Paragraph 12

During the third millennium BC, there developed a very intimate cultural symbiosis between the Sumerians and the Akkadians, which included widespread bilingualism.

The influence of Sumerian on Akkadian ( and vice versa ) is evident in all areas, from lexical borrowing on a massive scale, to syntactic, morphological, and phonological convergence.

This has prompted scholars to refer to Sumerian and Akkadian in the third millennium as a sprachbund.