"He's not an avatar anymore, is he? Maybe we'll call it Na'vi."
As for the story, a second Avatar film would emphasize the spiritual aspect of the Na'vi even further than the original, he said. Avatar was primarily an action/adventure with the spiritual nature of the Na'vi at its heart. Now that audiences have embraced the Na'vi culture, Cameron can give it more weight in the sequels.
http://scifiwire.com/2010/03/james-cameron-dont-call-i.php