Scholars have completed a dictionary after 90 years of work. Considering the language they were working on is 4,500 years old, they made pretty good time.

The University of Chicago's Oriental Institute this week announced completion of the Chicago Assyrian Dictionary, a work begun by institute founder James Henry Breasted in 1921.

The 21-volume, 9,700-page opus identifies, explains and provides citations for the words written in cuneiform on clay tablets and carved in stone by Babylonians, Assyrians and others in Mesopotamia between 2500 B.C. and A.D. 100. The first 20 volumes were published as they were completed, but now the work is complete.

"I feel proud and privileged to have brought this project home," said Martha Roth, editor-in-charge of the dictionary, which has about 30,000 entries. She's a late arrival to the project, having only worked on it for 32 years.

"It is a language that is no longer alive, this is absolutely true, but it is a language that records a society and culture that impacts the Western world in a way that is not always clear to us," said Roth, who is dean of humanities at the University of Chicago.

Other than glimpses provided by Hebrew and Greek writings, the modern world knew little about ancient Mesopotamian cultures until 19th-century scholars started to decipher cuneiform inscriptions, Roth said.

"We began to see entire civilizations that had been thriving, flourishing for 3,000 years and more," she said. "This was 3,000 years of history that we've discovered."

Compiling and defining every word of the ancient language allows us to glimpse everyday life in that place and that time and draw connections to our own place and time, Roth said.

The writings gave us "the histories that went into forming who we are," Roth said. They told a creation story older than the Hebrew creation story, told a flood story that preceded the Noah story, and described a code of laws that predated Moses, she said.

Robert Biggs, professor emeritus at the Oriental Institute, worked on the dictionary and also as an archaeologist on digs where he recovered tablets.

"You'd brush away the dirt, and then there would emerge a letter from someone who might be talking about a new child in the family, or another tablet that might be about a loan until harvest time," he said. "You'd realize that this was a culture not just of kings and queens, but also of real people, much like ourselves, with similar concerns for safety, food and shelter for themselves and their families.

"They wrote these tablets thousands of years ago, never meaning for them to be read so much later, but they speak to us in a way that makes their experiences come alive," Biggs said.