Akkad was the capital of the Akkadian Empire, which was the dominant political force in Mesopotamia during a period of about 150 years in the last third of the 3rd millennium BC.
Agade-ki ("Country of Akkad"), on a cylinder seal of Shar-Kali-Sharri.
Akkadian is an extinct East Semitic language that was spoken in ancient Mesopotamia from the third millennium BC until its gradual replacement in common use by Old Aramaic among Assyrians and Babylonians from the 8th century BC.
Akkadian language inscription on the obelisk of Manishtushu
A Neo-Babylonian inscription of Nebuchadnezzar II
Georg Friedrich Grotefend
Edward Hincks