We live in Switzerland but speak English. Our AppleTV movie choices to buy are all in German. We can choose movies in French or Italian but we want our movies in English. If we buy a movie in German, for example, can the language be changed to English?
Each studio will make decisions for language support for each title. In countries where English is not a main language, English may or may not be included. Probably mostly when English was original audio, not for regional movies. You can read the available languages on the Details page for every movie (before you rent or buy), under the Languages heading. You’ll have to choose from what has been made available to you in your region.
To change the language from the default to an alternative language (when available), see:
Change subtitles or audio languages for videos in the Apple TV app - Apple Support
E.g.
Honest Thief has German and English audio in Switzerland
Raya and the Last Dragon has German and English audio in Switzerland
Yamato has German and Japanese audio in Switzerland
Platzspitzbaby (actual Swiss movie) has German audio and English/French/German subtitles in Switzerland
Serenity has German, Italian, and English audio in Switzerland
Soul has German, Italian, French, and English audio in Switzerland (but as 3 separate purchase options!)
You can only get the languages that are available in the store in your country, usually, that means the languages of the country. I would suspect that many/most of the movies offer English subtitles.
Changing languages of movies?
