Not out loud. I’ve done enough on stage, with and without microphones, to know that in general I should smile hopefully and try to let the words speak for themselves, or have someone else do it.
I do run them through over and over again in my head. I think that my characters, when I create them, have their own voices, and when there’s dialogue going on I can hear them, as well as if they were being spoken by actors, certainly much better than I could do it myself.
I’d be fascinated to hear you, Oliver Shiny or any of the other distinctive voices who wants to do this. Fascinated, but possibly no more than that, because thereafter every read would be coloured by a memory of the author’s voice. Some writing benefits from that. And some — I offer you as a horrifying example Dylan Thomas — doesn’t.