I hear a song like this and when everyone is asleep I painfully transcribe it and try to hunt down the lyrics somewhere. I haven't been lucky finding Paulinho da Viola lyrics, though, so I'm thinking of recruiting some parents from Coco's class. They're Brazilian, so they might be game - I've already recruited the mom's help in translating a Chico Buarque thingie (for which I found the lyrics online).
Here's the song. Get back to me in a month and I might be able to play the first verse at half speed.