I just downloaded the massive Chicago Assyrian Dictionary, 90 years in the making! What an invaluable resource that preserves languages and cultures from more than 3000+ years of ancient Mesopotamia. This dictionary is useful for so many reasons, including Semitic Philology.
Ancient Mesopotamia is the cradle of Civilization. Between the two rivers of the Tigris and the Euphrates some of the worlds earliest villages, towns, and cities were established, some of the worlds first palaces, kings and laws emerged, as well as so many other elements of civilization such as agriculture, art, religion, writing, etc. The languages that dominated this region for thousands of years have been cataloged in the Chicago Assyrian Dictionary (and the project is still ongoing).
To learn more about Mesopotamia, one can read a book review I wrote a few years ago about an accessible history of ancient Mesopotamia called “Civilizations of Ancient Iraq” by my Akkadian professor at Yale, Ben Foster. Or visit this website from the University of Chicago: http://mesopotamia.lib.uchicago.edu.