Gonzalo Rubio spends his days reading dead languages that haven't been spoken for thousands of years. An assyriologist at Pennsylvania State University, Rubio studies the world's very first written languages, Sumerian and Akkadian, which were used in ancient Mesopotamia (an area covering modern-day Iraq). Sumerian appeared first, almost 5,000 years ago around the year 3,100 B.C. This writing was scratched into soft clay tablets with a pointed reed that had been cut into a wedge shape. Archaeologists call this first writing "cuneiform," from the Latin "cuneus," meaning wedge. Sumerian and Akkadian were the languages of the ancient Mesopotamian civilization, which...