They can use any voice they want, they try to make it a subliminal thought to the person they are using ie a celebrity, dead person, or relative. basically anybody. They can make a voice come out of them but it doesn't make them use there lips. That's how you know its not the person. None of the celebrities I've met really know me. The person that is suppose to be murdering me is half a sleep now, I can tell because of the time 5 am, and he sounds dead tired.
So you may think its a certain person but they just use people to give you the wrong idea.
For example I watched a movie of Hitler on ww2, then Hitler starts to talk to me, he isnt alive but he they can go into their voice and say anything and it will sound like them minus the emotion. Im sure he would have been madder at me for what I was saying.
I had a conversation with my cousin, the way she was answering without her lips was common. I started asking her questions about my childhood. She knew some because I was giving the answer away before the question. She also sounded like a robot. Then when an actual person goes into the persons head to talk you can tell.
I hope this helps others.