If the voices are in the memory, then it is normal. I hear people say different thing too. Like one time i was writing an email...and i wrote something other than what i herd, but then i herd a pastor's voice say what i was supposed to do....so i knew it was God getting my attention to write what i herd the first time.
Other times i have herd people say things just in their way, and it was their voice and it was just my brain remembering something that made me smile. So that is why in my opinion it has nothing to do with demons.
We have to be careful, when thinking that the devil is hiding under every rock. And then there is the other side where people do not think the devil does not exist or has no power.
So as not to confuse a young Christian this discussion should be done just as if parents were having a discussion that the kids should not be apart of.
Blessings to you all
That is exactly my feelings as well. Excellent comment!