One aspect I didn't see in the earlier learning thread is immersion in the reality. A song is a slice of experience -- doesn't matter if it is real or imagined although real ones have more power, I think. You anchor yourself in the story and the song becomes second nature, like knowing your own phone number. I don't know if this makes much sense or not; but it works for me.
Instead of using a osng's words to evoke a copy of an experience in others, I try and recreate a chunk of the experience, and find that much easier to recall. When I have such a chunk, the song is just what I would feel like saying anyway.