Hi ! In TV-Series, some features that are available for movies are missing, especially in relation to international TV.
There is no Filter by language in the filter criteria list. We only can do an intelligent collection by language but it’s not the same and not as useful.
There is no Country metadata. This is inexplicable because I’m sure the metadata providers have this information.
A TV show as such doesn’t have a language.
Only its episodes have audio and subtitles in (potentially) various languages.
You can create an Advanced Filter in clients which support them, to filter for audio and subtitle languages.