FEATURE REQUEST - Default Audio and Subtitles Per Library; Not Just Per User

Has anyone actually tried using multilingual audio on Plex (or any other Media Player for that matter?)
I don’t think I am alone in having a multi-lingual family. Most members speak more than one language.
Everyone seems to assume that as a user, you will have a default language and want to watch everything in that language. That is really not hte case in today’s world as people who speak more than one language will actually prefer to watch using the native soundtrack if they understand that language rather than watching a dubbed version!!

So having a default language per user, although being good for some, is useless for others.
Most people do not want to have multiple rips of movies or TV, one for each language and thus the use of multi audio tracks.
Would it not be really simple to have one rip of TV series or Movies using multi-audio – even just two tracks – then creating two libraries, one for each language (set default in each library) but pointing to the same files with the multi- audio track? Then you simply choose the library based on the language you want.

You may say, why not just select the language when you play. Well, that may work if you are using the native Plex media player but lost of the players, and TV DLNA systems do not support multi-audio but they do support multiple libraries.

I would like to have three libraries for many of my movies, Mandarin, Cantonese and English. I can choose English while my kids can choose Cantonese or Mandarin. One copy of the movie each with 2 or 3 sound-tracks. This would solve many of the audio track issues which now require a dedicated file for each language to make them practical to use.

I also think that this could be very easy to implement

An aside to this? Is there a standard for the choice of languages? Most systems show Chinese as a language when actually there are two main flavours; Mandarin and Cantonese. I am currently having to enclose Cantonese under something like Czeck or another language I will never use as I can’t separate these two Chinese languages. DVDs seem to have 2 digit number code for audio tracks. Is there not a standard coding system that would let one choose a default language in Plex that could then match what was in the video file. There is a strict convention for naming but I cannot see anything about audio tracks. When you choose from the player, it is reading the file so knows what it contains. But if you are setting defaults, you are not reading the file so need to have a convention for correct matching.

I would also like to have a language settings per library. That would be very useful for section like american series and japanese series.