Pre-sleep flashes and sounds

I have flashes of scenes from dreams I've had just before I fall asleep. It's really weird as the 'flashes' could be from a dream I've had a week ago, or possibly one from years ago.
I've also been 'hearing' things just before I actually fall asleep- nothing that makes sense- sounds like a language of some kind, but nothing I recognise. In my half-asleep state I'm aware of thinking that I should wake up and write it down- as I can never remember it the next morning.

Has anyone had this?