Modern schooling and my geneological linguistic upbringing are not valid comparisons for medieval education.
Still, even if five is a high number, actual historical language-learning practices can be looked at for reference. Pretty much
every major medieval scholar was a polyglot. Granted, they learned Latin and Arabic, and in some instances Greek - these were intellectual languages, but the point stands that it was very possible in the medieval ages to learn multiple languages. I think it's fair to compare some aspects of the Renaissance to Regalia - Copernicus for instance knew his native Polish, as well as Latin, Greek, Hebrew, Italian, French, and German by the time he was thirty. This was at the same time as learning many other disciplines, because learning multiple things at once is quite possible. He's a special case as a genius, but the point stands.
Keeping it purely to the medieval ages: Even among laity, knowledge of Latin was relatively common, especially in urbanized areas. Often if you were literate, it meant you spoke at least one other language. If you were a scholar or nobility, it often meant you spoke more. In England, for instance, it was common for nobility to speak French, Latin, and English. In Regalia, that would equate to the common language, the cultural/ancestral language, and the legal/scientific language. The circumstances could change as roles overlap and such, but the basic idea is realistic.
I guess my point would be that even if you can say that five is not the
norm, there's precedent for being able to speak multiple languages in a medieval setting. Quite a lot, honestly. I can see why OOC you would put quite a lot of restraints on knowledge in general, because there's a strong pull towards overuse of physical and mental abilities creating übermensch super-characters who exist to fulfill power fantasies and offer nothing tangibly
good to an RP. Still, there may be a bit too strong a restraint on the ability to be an educated character, to the point that it's unrealistic - you can get around that by saying that your education is quite good in aspects that just aren't dealt with in IC rules, but it's a little frustrating that educations take six, seven, eight years of
exclusive learning in that topic to reach even an adequate level when in reality Universities - a medieval concept - historically taught many of those subjects in the same to less time all at once. The medieval curriculum - lifted largely from the Classical era - involved many practices that some schools use today because of their effectiveness. It often involved reading detailed accounts written by and about important historical figures, which is why private tutoring flourished as well - "Sit down with the book and read, then discuss" doesn't require a lot of materials.
Obviously this is your own lore, and you make your own history and internal considerations when choosing the restraints on these things, along with the fact that you have to rein in RPers. Still, medieval education, especially in the eras that Regalia is largely comparative to, was pretty good. Less accessible, yes. It's entirely fair to say that the vast majority of people would be less educated than most people today, and education was pretty much entirely restricted to the very rich and the nobles. But though it was historically
quantitatively bad, it wasn't
qualitatively bad.
Just for your consideration if you're reviewing the language issues. I didn't mean to make some really long post, I just have a real problem with doing that.
TLR: Learning a language isn't
that hard. Besides that inherent point, Medieval education was not that bad: In fact knowing multiple languages was relatively common among the nobility and higher classes, even in some circumstances the urban class in general. I think it would be fair to restrict knowledge to certain backgrounds in general, on a grander scale, but loosen the restrictions on how it's handled on a smaller scale. Still, it's your world, and you can easily rationalize most things and I understand why you would for the sake of RP.