In James Cameron’s 2009 film Avatar, the Na’vi speak the Na’vi language.
Na’vi is a constructed language created for Avatar by linguist Paul Frommer. James Cameron wanted the inhabitants of Pandora to have a complete, consistent language rather than random fictional sounds. Frommer developed its vocabulary and grammar to make it pronounceable by the actors while still sounding unfamiliar to English-speaking audiences.
The language is used by the Na’vi characters, including Neytiri, and appears alongside English in the film. Actors learned lines and pronunciation for performance, and the language became popular with fans who expanded their knowledge through published materials and online communities.
Na’vi is not the same as a pre-existing Earth language, although its sound system and grammar were designed with recognizable linguistic principles. The film’s title uses Pandora for the moon where the story occurs, while Na’vi names the indigenous people and their language. The language therefore helps distinguish the fictional culture from the scientific setting.