Na'vi
The Na'vi language is a constructed language. It was made for the movie to be spoken by the actors when they played Na'vi characters. The Na'vi language was made by linguistics professor Paul Former of the University of Southern California. Frommer made the language so it could be spoken by human actors. It uses syntax and grammar from real languages. The professor made up over 1,000 words for the Na'vi language. He taught the actors who played Na'vi characters to speak it for the movie.