Wow that’s very interesting. Did you know about that case before yesterday?
Hearing voices before falling asleep is common in healthy people. I know because I suffer from it. It’s called hypnagogia and the most common cause is a disturbed sleep pattern. We also discussed it in this topic: Circle Casting gone wrong? Check it out as there are some more tips in there.
I had these hallucinations when I was in high school and would stay up until late. Then as I fell asleep I would hear noises outside the house, just like you describe: people talking out in the street, loud banging or yelling, but I’d look out and see nothing.
I did some research online and found out what it was. I fixed my sleeping pattern but it still happens to me sometimes if I fall asleep in an uncomfortable position, or with the lights on, or anything outside of normal.