In Happy feet Why is Mambo nicknamed Mumble?
"his name is just mumble he was never nicknamed"
I believe his actual name was Mumble - because he could not sing
when he was born. In the group dance scene - right before Mumble is
kicked out - his peers nickname name him Mum-Bo! I think just
because it's a cooler name, and it's a sign of him finally being
accepted amongst his peers.