Avatar: Fire and Ash is listed under the English language on Wikipedia.
That label appears in the film’s infobox, alongside its country of production, release dates, running time, budget, and box-office figures. It identifies the language of the motion picture—not the language of the Wikipedia page’s navigation system or its international translations.
The film is the third entry in James Cameron’s Avatar series and follows Jake Sully, Neytiri, and their family on Pandora. Although the Na’vi language is central to the fictional world, English is the listed language for the film. Na’vi is therefore a tempting but incorrect option: it is a constructed language used by characters, while English is the production’s official infobox designation.
Wikipedia also offers the article in many other languages, including French and Spanish. Those are translations of the article, not the language listed for the film itself. The distinction between an article’s language and a film’s language is the key to this question.