 Old Akkadian, which was used until the end of the 3rd millennium BC, differed from both Babylonian and Assyrian, and was displaced by these dialects.By the 21st century BC Babylonian and Assyrian, which were to become the primary dialects, were easily distinguishable.Old Babylonian, along with the closely related dialect Mariotic, is clearly more innovative than the Old Assyrian dialect and the more distantly related Eblaite language.