Cahptan! Ahm givin’ er all she’s goht!

So you’re the Storyteller… and you’re the worst actor in your troupe.  Oh.  Wait.  That’s me.

You have an entire city, or (shudder) several cities worth of vampires to portray.  And sadly, not all of them are going to share your mannerisms or your accent.

You’ve got a couple of options.  If you can pull off a decent accent, feel free to do so.  However, if your Assamite assassin winds up sounding like Apu from the Quickie Mart in The Simpsons, it’s going to nigh impossible for your troupe to take him seriously.  Your next best bet is to lay the description on thick and include the accent as a part of the description, letting their imaginations add it in.  If you can adopt some cultural mannerisms or speech patterns without hamming it up, you can get the point across without being distracting.

In my not-so-humble opinion, if all your NPCs wind up sounding exactly like you, it’s not because you couldn’t pull off an accent, but because you haven’t made them come alive in your players’ minds.  If the character’s ethnicity is a vital part of their character, then their ethnicity should show through in many other ways besides the way they talk.  If it’s not essential, then neither is the accent.