It's not obvious. For years, we were told we weren't supposed to know who Vodul is, even though Vodul is in the settings.
Seems obvious to me that Vodul is therefore in the half of settings your character doesn't know
It's a medieval setting so most people should be fairly ignorant when it comes to understanding the workings of the social order, unless they have personal involvement or experience.
Do not confuse Medieval with feudal, Yliakum is a small insular society with a small population, so most people should have a fairly good understanding of their position in society and how to improve oneself.
In medieval times, literacy was low, and access to books was a privileged of the few. As far as things having "correct names", history tells us that specific locations can have multiple correct names in real life.
Refer to my answer above do not confuse Medieval with Feudal, literacy was low in medieval times because of the lack of economic access to books and the written word also church control and other issues, however Yliakum has an abundance of books all freely available in the library, everyone who crafts has books.
See? It's complicated.
Sorry but no I don't see, even before I became a GM/joined Settings I understood the relationship between what my Char knows and what I as a player know, it only becomes complicated when over analysing.