In this video, MonotoneTim converted The Bee Gees' Stayin' Alive to MIDI: the sound of the song, rather than its individual notes.
The result, an endless mash of piano noises, eerily and rather unpleasantly replicates everything in the track, right down to Barry Gibb's falsetto vocals. This is described as an "auditory illusion."
Aside from the fact that the result sounded like a piano factory exploding, I also could have sworn I heard sung lyrics in it, even though the only midi track was a piano. Not sure how the converter works, but I guess the way vocals are recreated via piano is similar enough to the real song for our brains to mentally fill in the words where there aren't any. Maybe? Pianos usually don't talk.
Let me know how well you hear the lyrics, if at all, and what other songs you tried!
It's seems like a vocoder. So many notes are playing that it merges together to becomes a staccato droning noise, which is then modulated by the song's waveform into an audible semblance of the lyrics.