Dragon Quest IX isn't be the most innovative RPG ever, but it does have a rapping priest. Well, a priest who speaks in a hip hop dialect.
Actually, though the mechanics are simple (a little backwards, even) and the play straightforward, Dragon Quest IX does have eye dialect. It's the first RPG I've seen in which every town has a slightly different accent. There's a Scottish brogue in Stornway, a bit of a Cockney thing going on in Dourbridge, and a wandering priest that speaks the language of the streets (well, Will Smith's streets, in the 90s).
This linguistic touch makes every area feel different. Much the same way that giving each town its own music would (and does in most other RPGs). Dragon Quest IX takes the road less travelled in that regard, though.
And, the game's job system and bosses aside, I think its linguistic variations are for the better. They make the game's already extensive world feel as though it's populated with an extensive range of people rather than generic NPCs.