Enable captions and subtitles in embeds by default

Hi, we would like to enable captions and subtitles by default. We know that we can do so by adjusting the embed code before placing it on the site. But that’s quit complicated for non-programmers. We think, there should be an Option in the embed setting (analogous to the playback, video and advanced settings). OR: Is there a filter to manipulate the player url? That way we could dynamically add the active language code to the player url (e.g. we could add this to the url, when the user views the site in german language: &texttrack=de).