Also, it'd be like the Rosetta Stone. Comparisons between different languages that say the same thing is a good way to figure out what they're each referring to, if remnants remain.
I can't help but wonder about the realistic logistics of putting this out in the middle of Kudzu country. There are massive pyramids that have been buried under the jungles of central America. So what made them think any post apocalyptic peoples will find this "guide" before they are already advanced enough to have some form of archeology?