Change language on the fly?

I live in the UK in an area where apparenlty 28 different languages are spoken within the region and I'm sure mine is not the only one.Would it be possible for viewers of a video would be able to change the language within the video using a dropdown? This would enable one video could be sold at a much higher price because, 1. no-one else is doing it and 2, only 1 video would be needed to cover a variety of languages. Not sure if this is possible but would be a huge step ahead of the competition.