When I want to buy or rent movies the language is Thai. I have set in Audie the main language as English with Thai subtitles but no good.
You can set the standard audio language and subtitle language in Settings﹥Video and Audio﹥
﹥Audio Language
﹥Subtitle Language
This is separate from the system interface language of the device.
You can also change the audio language and subtitle language while playing, by swiping down to access the Info | Subtitles | Audio overlay menus. Change the subtitles or audio language for the Apple TV app and iTunes Store movies and TV shows - Apple Support
Available audio languages and subtitles may differ by title and region. Preferred languages may not be available on certain titles in your region, but you can check that before you make the purchase.
How do I change the App Store the device is registered with.
The region for the iTunes Store and App Store has to match the region for your Apple ID, as determined by billing address and payment method. If they don’t match, then you can’t make purchases there.