the problem is having a wide spectrum of knowledge checks condensed down into two checks like you have is you end up with one definite choice over other skills. its why i split up the numerous knowledge skills into 5 groups that relate to the uses of the skills.
Linguistics also contains Forgery in pathfinder, which is a skill that contains 3 unrelated skills that happen to all rely on language. Literacy is outright ignored in PF at that, as a skill that really should be inherent. You can speak a language and not be able to read it, or you can read a language without being able to properly speak it.