Apprentices in Grammatical Places

You are a group of mischievous apprentices studying under a mad wizard who specializes in the art of spell rewriting. Through their studies, they were able to figure out the power to shift the reality of objects and spells by changing their names. One evening while your master is out of town, you were able to get a hold of their spellbook. By coincidence, a group of magical thieves who have heard about this magical tome has come to claim it. You must protect this tome with all of your combined might and cleverness.