I'm also finding far less nonviolent ways to convince people than I expected. Nearly every solution to talking with someone almost always ends up in a fight.
BG has a weird design. You won't find charisma checks or things alike. However you will stumble upon 15 different generic gentlemen who all have their unique way to tell the peasant pc to fuck off.
Now, I suggest that you keep paying attention to dialogs though, there are a lot of them with specific outcomes. The thing is, it doesn't revolves around checks or obvious choices as with your typical game, but prefers the whacky way. For those dialogs, the best way to know the correct answer is to randomly select it.
So, yeah, weird design. Imagine that you're playing a standard DnD adventure with a rather goofy DM, basically.