I think even if you go on holiday somewhere you should know a little of the language. It's rude not to speak the language of the place you're going to/living in, as it causes so many problems for others.
But then, it depends of where you live - if English is the most popular language spoken in a certain area, but there's a small group of French-speakers, then wouldn't it be bes tto try to learn a bit of both? Or whichever you find yourself the most capable with. At least, then you can work/live with the people who's language you speak.
But then, shouldn't the world have one universal language to get rid of this kind of division? And I don't think it's fair for it to be an already existing language, as it puts some people at a disadvantage.
So, we need a new language that everyone is made to learn from the start of school from now on. It may not work for our current generations, but there will always be more children, and this will enable the world to become a more unified place.... maybe?
It's going to take a while.
On the subject of the topic post, I don't think everything should have to be English. Language is useful, butthey should make allowances for other cultures - and language is a big part of culture, isn't it? Have I just contradicted myself?