given that the whole historical mechanic is really just a VR experience of “genetic memories” run by an evil corporation (Abstergo) it stands to reason they would selectively edit certain aspects of history to suit their purposes
(just to play devil’s advocate for the writers, heh)

aside from his mandarin, basically every one of his videos where he ‘speaks fluently’ in one of a hundred other languages involves him basically stammering repeatedly while trying to get out a simple phrase, as though the elongated time it takes him to say
‘I-I-I-I’ve b-b-b-been l-l-learn-ning f-f-f-f-for t-t-two w-w-eeks’ counts as a lengthy, fluent phrase