Avatar geeks everywhere, here it is. Finally. A bonafide primer on the Na'vi language.
The Na'vi language is indeed real. It was created by USC Professor Paul Frommer (an expert with a doctorate in linguistics, no less!).
Apparently learnnavi.org is young and still growing - "So far, we have a ~500 word Na'vi-to-English dictionary, the basics of speaking/pronouncing Na'vi, and an in-progress grammar and syntax section".
Download your own Na'vi Pocket Guide.
Artwork via The Art of Avatar.