At level one you get PowerPoint, at level two you get Excel,....
I would say you are correct, Thrud. However, that's why Mage's Guilds exist...to make sure outsiders aren't learning their secrets. Or, you could take the Shadow World approach, and give each realm its own magical language. Thus, only followers of the Dark Gods would be able to read books in Var Arnak, only Essence users would be able to read books in Uscurac, etc....