Actually, wouldn’t Beast already know how to read from his human days?
I think in the song they cut from the movie, then reintroduced with the re-release, there was a few lines where Beast either admitted he couldn’t read or the book was just too difficult.
Given that he was a spoiled brat of a human, it’s not unlikely he just didn’t try to read! Like he was capable but didn’t bother learning more.
(Source: pandaaamonium14)
