Personality affect voice?
No, it doesn’t. Only race/sex determines your voice. Class determines what skill-specific lines you have.
They probably sound different because there aren’t variations on any lines. So hearing the aggressive “Attack!” from a ranger will sound different than a warrior’s “On my Mark!” even if it’s the same voice.
That would be really cool if it did, though I heard that personality isn’t really as present in-game now (I started recently). I really liked how in Dragon Age 2 the PC’s voice and mannerisms would change as you got more set in a certain personality. But I suspect that would be a lot of content to pull that off.