Passage: After the end of the Mesopotamian kingdoms, which fell due to the Persian conquest of the area, Akkadian (which existed solely in the form of Late Babylonian) disappeared as a popular language. However, the language was still used in its written form; and even after the Greek invasion under Alexander the Great in the 4th century BC, Akkadian was still a contender as a written language, but spoken Akkadian was likely extinct by this time, or at least rarely used.  The latest positively identified Akkadian text comes from the 1st century AD.

Question: What disappeared as a language at the end of the Mesopotamian kingdoms?
Akkadian