What I mean is that if you look at the written scripts for the characters, the structure of the sentences across companions are fairly similar. Like [adverbial clause][addressing noun][adjective] etc. Every character has their own personalities and manner of speech for sure, but they are fairly homogenized in the syntactic and connective quality of their speech.
Ah, I had thought that was only part of your point and you were also talking about differences in mannerisms and the way they spoke more broadly.
I agreed on that specific point about syntax, but as I said I would put that down to the four other than Lae’zel all sharing a language. Different sentence structure to me usually just comes across as annoyingly affected unless it has a rationale, usually in the form of different first languages or at least different dialects.
So, if you think about DA:O, we have Leliana from Orlais, Zevran from Antiva, Sten who is Qunari, Oghren from Orzammar, Shale from a long time ago, and so on. They are a more geographically diverse bunch than the companions we currently have in BG3 so different grammar because of different languages and dialects makes more sense than it would for our four Sword Coast natives.
Or perhaps I am still misunderstanding your point?