That is just the premise of this game: MC is not a schooled individual, not like going to school or going to the tribe old lady who tells the stories and all the kids grow up spinning the tribe stories until they are all grown up and start to understand all that stuff.
We do know MC has the exact same upbringing as the son of the Princeps, being bred to be with the family and guard the family, but nothing speciffic about how precisely him and the prince got to learn how to speak, how to read, their skills, we have nothing really for us to understand what is it that they did until being 27 and getting antsy about the same old Princeps and his well travelled ways and means of ruling their world.
They speak harshly and quite devoid of color, certainly not very narrative like, because MC is a killer, assassin of the creed to follow any and all orders of his Princeps. We know MC and the prince and some others we never get to know use weekends to go fish and drink their lives away - so pure machismo manly weekend gettaways - but we are yet to see any woman decorate their lives - so of course their conversations are rather blunt. Seeing as MC is in the fringes, remember the talks about the northerners and the Empire talking about them like barbarians - that is how MC is, a skilled viking assassin, but still the assassin, not the noble prince that talks like a chatter box. We have a clear divide between the Loki like princes who talk with no bite and the adopted skilled assassins who use their ccraft and their deeds to do the talking more than their tongues ...
Its whole text structure and vocabulary is kinda weird
The way NighOwl tells it - MC could just be another pod baby, awaken when the Princeps found some volt or another.
We could be overthinking this even more and make the assumtion Princeps got MC and his son as a present from the Empire when they struck the peace treaty - they have authonomy but the empire holds precedence and they are not warring still.
This is because we only ever hear about the dad of MC or his mom from the Princeps - nobody else ever tells of ever knowing them, not to mention nobody ever talked about how his won son manifested or about his wife or the mother of his son.
It could be that Dad brought MC back home after one of his warring missions - or MC dad spared the mom of MC and wed her and they had a baby, or he took her slave home, made her his woman and they made love to procreate MC - like Stavros is outright telling MC to do to find a girl for himself - His girl still finds her way into his chamber and they play games together.
These are missing pieces that are logically missing from action oriented games that do not have narration over beautifully rendered cut scenes that tell the story ahead of us actually seeing the characters on the screen and reading their dialogues.
