I was looking at the TVTropes entry for The Mirror of her Dreams and I found myself suddenly recalling bits and pieces of what I think was a different novel that I read at the same time (so somewhere in the later 1990s) as a library book from my hometown of Ashland, KY. The main character is apprenticed to a master, I believe for some sort of functional magic. Unfortunately, the magic bit is not firm in my head, but the method of language training is. Specifically the master had him learning some foreign language by the deep immersion of only using said tongue, and forcing the apprentice to learn to think in said language, which culminated in a scene where the apprentice was holding a frying pan coated in burnt egg and in despair because he can think of none of the words he needs, including that he needs some jeweler's rouge to help him scrape the pan clean. The other bit that sticks out in my head was that he learned that the foreign word for his culture translated out to "wrapped in maps". Unfortunately, my keyword searches seem to be for naught.
I do remember this as being a hardback book. It would almost certainly have been published before 1998, when I graduated, because I remember it being associated with an earlier segment of my life, when my older brothers were actively checking books out from the library. I don't remember much about the setting, other than what I noted about the language, but it was definitely pre-electronics, probably at the level where glasses were being ground out to fix severe vision problems but not enough to be common, unsure about the status of gunpowder. The magic was knowledge-based, but I don't think it involved the traditional arcane trappings of candles, incantations, and summoning circles.