Mumble tap dances while he walks on ice. Tap dancing while wearing tap shoes, when you're on smooth surfaces, prevents you from slipping.
Mumble came out of his egg feet first (as opposed to using his beak like birds normally do). Technically this means Mumble was born in the breech position. Breech babies tend to have a higher risk of having developmental problems.
The tendency of overenthusiastic suitors to drown out a particularly desirable female in their attempts to woo her leads to a sort of Fridge Heartwarming moment when Mumble finally embraces his dancing; not only does his "heartsong" match hers perfectly, but he will never drown her out. Rather than trying to convince her to accept a melody that isn't hers, Mumble provides an independent but perfect harmony that makes both of their songs more beautiful.
The rockhopper penguins speak Spanish because they're from South America. The elephant seals speak with an Australian accent because they congregate near the part of Antarctica that's close to Australia and New Zealand.
During Mumble's Sanity Slippage, his father is standing with his back to him, because they haven't reconciled with each other yet.
The African penguin in the exhibit speaks in a creepy monotone and repeatedly calls Mumble "Dave". Perhaps his name is Hal?
Even the hallucinations of Mumble's family start calling him Dave. Mumble doesn't question it, as he's also lost his mind by that point. It's a really unsettling side effect of being in an enclosure instead of in the wild, and tragic that even the humans who want to help still end up causing some harm.
