"Us Monkeys Together" is sung in Mandarin. Being Chinese myself, I can say that there is an English-accent to the Mandarin, but it's very bearable (I wasn't expecting there to be a Mandarin song on the album!)
I've been waiting for this album since I read about it 2 years ago? I was not disappointed! My favourites from the album are: Bramble Reprise, Castle Crescendo, Dance of the Zinger, Roller Disco, and Crystal Swamp (all from Disc 2).
I have to mention that Dance of the Zinger blew my Asian boxers off. I used to pause the game on that level just to let the song play in its entirety.