The language spoken by the alien characters is a real language called Kaingang, a Native American language from southern Brazil.
The director's former USC roommate, screenwriter Brad Riddell was set to perform all the film's motion capture, but the day before the shoot he injured his ankle playing basketball. Unable to reschedule the shoot, director Eric Law Anderson ended up performing all the motion capture himself.
The main character's eyes are based on the director's dog's eyes, using close-up photographs of her irises to build accurate replica eyeballs.
When Lufo looks at the blueprint for Planet 3 (Earth), he notices it is in Phase 42. This is an obvious nod to Douglas Adams' book series of "The Hitchhiker's Guide to the Galaxy."