So when I think in words, I think in a voice I like. One that conveys the desired sense of emotion that I'm then feeling. I usually use three, two more often then the third and each for different thoughts and moods. I have always based them off of the voices of real people, always actors or rather the a specific character they play. These are the ones I'm currently using.
I've been thinking with this voice for about two years now, ever since Tennant took over the role of the Doctor. He is the voice I use for most of my emotions especially the passion laden ones. He is also who I like to think in when when I am especially angry, the sound of his righteous indignation is especially impressive. In real life Tennant speaks with a Scottish accent, but he uses an English one for Doctor Who and that's the one I think in.
Damian Lewis as Charlie Crews of Life

I started using Lewis' voice before Life premiered on NBC, when I began watching HBO's Band of Brothers in which he played the lead. He normally speaks with an English accent but he used an American one on HBO and he uses on on NBC. He is what I think in concerning religious, spiritual, and ethical matters. His soft voice is very pleasant making thinking about God feel nice.
Jeffrey Donovan as Michael Westen of Burn Notice

When I need a calm in-control focus I use Donovan. His character on Burn Notice is matter of fact, straight to the point, sarcastic, and violent when necessary. I think in his voice the least but I've only been using him for about 6 months now. He comes in very handy when under stress, especially at school.
I want to make clear that I don't hear these voices; I think in them. They don't talk to me, they think as me. They are ways of bringing control to the stress of everyday life and I don't use them all the time. Now before you conclude that it's wired I suggest you try it. Just think you normal thoughts in the voice of your favorite actor or character they play (it's best if they are the same gender you are). You might find it's not so bad.