Literacy in D&D

The presumption of literacy in D&D has always been something that kind of bothered me. Assuming that all characters are literate breaks the willing suspension of disbelief in the implied quasi-medieval setting. 3rd edition codified that all characters are literate except Barbarians. Earlier editions just kind of assumed it, as evidenced by the presence of magic scrolls usable by anyone or magic tomes for every class*. I always went the other way in my campaigns, including my 3e ones, and assumed everyone was illiterate unless they had a good reason to be literate. Clerics and Magic-Users got a pass, I just reasoned that the level of education required for those classes also required literacy. This may be a little hypocritical on my part because I generally ruled that if you could do it in real life then your character could do it too, like with swimming.

Anyway, if you want your Fighter to be literate give me a reason. Maybe your Fighter was the son of a scribe or a librarian. Mostly I let the secondary skills table define your character's pre-adventuring past, but I am always open to working with a player that has a reasonable character background in mind**. I like a little bit of background for characters, it gives me something to build off of. If you do roll "no skill of measurable worth" I am willing to assume that you are a second generation member of your character class OR a younger son of a minor noble*** farmed out to an apprenticeship with your class mentor.

*I am willing to hand wave magic scrolls and tomes for Fighters and Thieves based on the fact that they are magic items. Maybe the scroll just has to be unfurled and displayed for the spell to take effect, or the magic in the scroll causes the words to usher forth from the character's mouth. Perhaps the tome just burns the knowledge it is attempting to impart into your head as you look through the pictures in the book. Plus Thieves eventually learn to decipher all manner of languages as a class skill.

**Reasonable should obviously avoid being ridiculously clichéd or uber-power-gamer-ey. I will die happy if I never meet another player whose character's family was wiped out by ANYTHING, I mean for god's sake don't any adventurers choose the life for any other reason than childhood trauma? Also princes and demigods and other super special or supernatural backgrounds can NOT show up again too. Whatever happened to wanting to be an adventurer because it sounded more exciting than plowing fields all day?

***Keeping in mind that nobles don't really get much of an education themselves in the middle ages, they keep literate people around mostly to do the stuff that requires literacy. They train in weapons and small unit tactics and estate management.