Sometimes during SP, I'll hear songs and people talking. A few times I've heard a radio playing in my head, with songs and people talking in between songs about random things that made perfect sense to me at the time.

Best way to do it, get a song stuck in your head during an ld, focus on it, and it should eventually start playing clearer and clearer, I haven't tried this yet though. But I'd bet it'd work if you could focus on it well enough.