Cuneiform is thought to be the oldest writing system, and it was first created around 5500 years ago. As writing was developed for different languages, scribes—ancient writing professionals— had to make sure people could read and understand the languages they were reading, as well as how to pronounce the word in another language. A lexical list from Iraq, pictured above, was how. This text allowed someone who could read cuneiform signs to be able to determine how a word was pronounced in both Sumerian and Akkadian. These two ancient languages both used cuneiform to write their different languages.

The "Chicago Syllabary", a cuneiform lexical list on clay tablet of unknown provenance, dating from the first millennium BC, is thought to contain content compiled earlier in the second millenium. 

"The text gives the Sumerian and Akkadian pronunciations of various cuneiform signs along with their names. As such, the text provides unique insights into how the ancients understood and analyzed their languages and the cuneiform script. The list is organized by sign shape. The table consists of two halves, with each half divided into four columns. The first column gives the pronunciations of a given sign and the second column gives the corresponding graph. The third column gives the name of the sign as given by the Babylonian compilers (in some cases a descriptive designation that blends Sumerian and Akkadian), while the fourth column gives the corresponding Akkadian pronunciation. In addition to the importance of its content, the text examplies the development of the cuneiform script in the first millenium BC" (Woods, Teeter, Emberling (eds) Visible Language. Inventions of Writing in the Ancient Middle East and Beyond [2010] No. 60).

The Chicago Syllabary is preserved in The Oriental Institute of the University of Chicago.