From what I gather Graphicmaniac, some are, and some aren't. For example, in the tutorial there's a Captain of the Ship you are on. He's actually Dwight Shultz apparently (guy from the A Team) He's adopted a pirates voice, and it's actually very over the top. ("Arrr, me ol scurvy swab, you best be killin' the rats or you'll be walkin' the plank" type of thing. I saw him speak in a short movie clip and noted he wasn't a very good voice actor - seemed to go from Hobbit to Welsh to Southern English. Might come from the Mel Gibson school of Unconvincing Accents
On the other hand, the Freeport head honcho Lucan D'Lere (voiced by Christopher Lee of LOTR fame) is actually very good imo. Some people have said some of the quest NPC's in the cities call out to you as you run past, and can be annoying when you've heard them x amount of times. I'm not in beta though, just going on what others have said. Not sure if their mouths are synched with what their saying or not though. I can't decide whether the voices add immersion or take away from them.