I think I know what you're getting at. I used have these "dreams" when I was in high school. My mom, my brother and I lived in a town house, we had a shared back yard with the neighboring townhouse however it was vacant, the people that owned it only came down to visit a couple times a year.
Anyway, I remember waking up many nights hearing people talking outside in the yard, in perfect english (my parents have a strong accent). Always different voices, always different topics. I'd run downstairs or look out the window, voices stopped and there was never anyone there.