You may know ALL the rules, but I KNOW the Spirit of the Game.
I think there is 2 basic considerations. 1) Are you playing a Game where everyone wants to just roll dice and have fun and work together. Or...2) Are you playing a Shared Story, where it is not so much about the rules as about the unfolding story and everyone adding to it.
all races should be able to speak their native tongue (whichever that would be, nation or race or group of races or nations), some trade and diplomacy language of the larger region (the so-called "common") and have an option to speak other, more distant languages. And end it at that
Furthermore, I don't know about the Latin based languages, but Medieval German, Dutch and English are surprisingly similar
and while deciphering such texts is not particularly easy it is not hard for me either
TL;DR, make languages based on political distinction, not racial.
Furthermore, a great majority of players and DMs could care less about languages. 95% of the sessions I've been in used nothing but Common. Languages like Elvish or Dwarvish are often just used to add ancient or exotic flavor to carvings on a temple or goblet.