Martin: Everyone was complaining to us about people not buying albums, so we thought maybe the reason people don’t want to buy music is because there’s not enough value for money. So we tried to add a bit of value [with the hidden track, “Chinese Sleep Chant”]. It’s as simple as that. It comes from the supermarket.

Champion: One of the main things we tried to focus on with this record is changing vocal identities, because Chris has a very recognizable voice. Just the idea that you can totally change the sound of a song and the sound of a band, just by treating the vocals a different way. So in a song like “Yes,” Chris is singing in a lot lower register, and then in “Chinese Sleep Chant,” it’s drowned in reverb, and he’s trapped behind all these guitars.

From a 2008 interview with MTV.

According to Songfacts, Chris Martin explained to Q magazine:

The lyrics aren’t Latin, no! I will say this, if you take away all the guitars, what you’re left with is quite ordinary. But Jonny (Buckland, lead guitar) will always make things less ordinary. Without him we’d be f–ked. It’s true!