Interesting question! Very similar I think. In your example if I say I want to travel all around the world it would mean I start from London and travel east (or alternatively west) and go through Europe, Asia (maybe a deviation into Africa) then Oceania, North and South America and back to London. If I want to travel all over the world then London is my base and perhaps I go to Africa and back then Asia and back etc. English is spoken all around the world English is spoken all over the world. I think these mean the same.

If there is a difference, it's pretty subtle. I tend to say "all over the world" more frequently, but I've written some examples both ways below, and they all sound perfectly fine. Number 3 is the only one where I'd be more likely to say "all around" than "all over," but I can't tell you why. My guess is you're safe no matter which you use. :) 1. He has been all over the world. 2. he has been all around the world. 3. All around the world people suffer. 4. All over the world people suffer. 5. There are wars going on all over the world. 6. There are wars going on all around the world. 7. His music is popular all around the world. 8. His msic is popular all over the world. (They both sound totally natural).