I would like to be able to use the original title only for all non-foreign movies. So, if my default language is English, any English title would use the original title.
For example, the movie 49th Parallel (1941)is a British movie with a USA alternative title of The Invaders. Since both titles are English, I want to prefer the original title.
Because my library contains foreign movies, I still need the English titles for those movies.
I’m not sure this would make as much sense with languages other than English.
You can edit movies individually and set the “Use original language” preference on them like that, or you could set the library language to “English (UK)” but that would obviously affect all movies.
That’s quite possible. But, that doesn’t make it any less useful of a feature; especially one that is hopefully a narrowly targeted change [testing only for language instead of language + locale].
Neither of these are an option. As you say, changing the library language affects all movies. And I can’t support untraceable / unrepeatable custom edits to media files. If I need to move / rebuild my database, I won’t be able to remember every one-off change.
NFO files are a potential alternative when that feature becomes broadly available. However, it means I need to find and manually change all instances where this occurs instead of flipping a single toggle.