Since Civ6's release, I believe the record holder right now is AoE4 with its extensive repertoire of Middle English and Middle Chinese lines even changing through the ages into Early Modern English and Ming period Mandarin, respectively. Though of course it was spotty. Persian got no such treatment and neither did Japanese.
Or are we going to lean more into\ artistic interpretation of the dialogues between leaders? Like with the civilisation drawings (Are these final or still a WIP, by the way? Ironically maybe a question you are more likely to be able to answer

).