I sent an e-mail that was not answered, perhaps I may have more chance here :
You could allow to have two simultanated subtitles shown.
This would allow non-english speaking people to learn very well English.
In fact, to have one subtitle that match English above and
upon a translation in another language could help improving English
vocabulary (for instance, in movies, I understand what they say, but
sometimes a word is missing in my vocabulary, and it would be nice to have it
translated upon the movie, in another font for it to be discrete).
I think this could be a nice new feature and would not give you much
work (re-implementing another subtitle display, except for the delay
functions I suppose).
Thanks trying to make a real good player (the only one I think is good
actually).
Have a great day.
Nick