The first known language in Mesopotamia, it was spoken by the Sumerian people who occupied southern Iraq in the 3rd millennium BCE. The cuneiform writing system was used to write the Sumerian language and then Akkadian. Sumerian is not related to any other known language. It was "agglutinating" because it works by adding prefixes and suffixes on an invariable root. Although Sumerian ceased to be a living language in Mesopotamia from the 2nd millennium BCE, it was still employed in some literary and scholarly texts after this date, and some Sumerian ideograms were also still in use.