Why is the Classical language even a thing?

Hello everyone!

I've thought about it for some time now and I really don't understand why the Classical language is a thing. I know it's meant to be a place holder for latin and it's the language of the Reman Empire, but since this empire's existence is very much subject to in-universe debate, why is their language something scholars would want to learn? There wouldn't be prestige and Tilea doesn't seem to be any more knowledgeable than other foreign souther nation (like Araby), so why would the intellectual and religious elites keep that language? Why wouldn't engineers and sigmarites learn khazalid, while magicians learn Magick and elvish and Ulric cult learns the language of the Teutogens?

I know the answer is simply 'they copied history so latin must be a thing', but it just kind of bothers me, especially since, in game, Classical language is a must-have for human knowledge except when it's not because the treaties are dwarvish, elvish, etc. so I think it's kind of useless and flavorless. What do you think?

Edit: I am speaking from the standpoint of the Empire.