This might be hard to do unless there is an open source website that already provides a service for clients to tie into. I’m guessing because vudu controls the content they serve they manually go through the movies and mark the scenes themselves.
For removing language, if one has access to the subtitles like opensubtitles or in any other text format like srt, then, it’s actually not that difficult since program can scan for the words you have configured and not play the sound during the subtitle time. This is similar to what Dish Network does with it’s Hopper (of course optional). Some players already use EDL files and remove the sound, for example Mrmc.