Ninety years in the making, the 21-volume dictionary of the language of ancient Mesopotamia and its Babylonian and Assyrian dialects, unspoken for 2,000 years but preserved on clay tablets and in stone inscriptions deciphered over the last two centuries, has finally been completed by scholars at the University of Chicago.

This was the language that Sargon the Great, king of Akkad in the 24th century B.C., spoke to command what is reputed to be the world’s first empire, and that Hammurabi used around 1700 B.C. to proclaim the first known code of laws. It was the vocabulary of the Epic of Gilgamesh, the first masterpiece of world literature. Nebuchadnezzar II presumably called on these words to soothe his wife, homesick for her native land, with the promise of cultivating the wondrous Hanging Gardens of Babylon.

On all levels, this was the language of enterprise, the irrigation of lands and shipments of cultivated grain, and of fate foretold. Medical texts in Babylonia gave explicit instructions as to how to read a sheep’s liver to divine the future.

At a conference on Monday, historians, archaeologists and specialists in ancient Semitic languages assessed the significance of the comprehensive dictionary, which Gil Stein, director of the university’s Oriental Institute, said “is an indispensable research tool for any scholar anywhere who seeks to explore the written record of the Mesopotamian civilization.”