Kassite (also Cassite) was a language spoken by Kassites in the Zagros Mountains of Iran and southern Mesopotamia from approximately the 18th to the 4th century BC. From the 16th to 12th centuries BC, kings of Kassite origin ruled in Babylon until they were overthrown by Elamites.Kassites in the Babylonian state used mostly the Semitic Akkadian language of the native Assyrians and Babylonians.