In terms of social class, yeah. He's made to sound like a military hick in comparison to some of the more sophisticated characters such as Kain, Cecil and WoL. Guys like Squall, Bartz, Zidane, Tidus and Firion sound normal in both versions though. Also with Kuja his voice actually changes between foppy and pontificating to normal when he (a) has a tantrum (b) is his 'true' self as seen in report 01 before the betrayal or during Shade Impulse when he's helped by Zidane. He had a similar schitck in FFIX where he'd switch from long, floral formal speech to short, casual sentences. And he'd use slang. (I'm a bit of a voice acting nerd)