I didn't even notice that I was doing it.
I know it's a habit of mind, but it's not something I do consciously. I enjoy it, though.
Maybe it's genetic.
I'm re-reading the Harry Potter series this summer. I love Rowling's tone in the first novel. When I was reading chapter 15, I suddenly remembered my first time reading the book. Grandmommy read that particular chapter to me. I could hear her voice in my head, reading the words in her way.
It's funny how that works, how you can imagine how certain people would say things, and hear it as if their own voice were speaking.