It will, probably, be inevitable, but I think for quite a while yet it will be most countries 'second language', even you need to have a level of English to be able to use the Web etc.
I think it would be a pity to see the end of other languages, but I agree with BW here, the chances are eventually that the world will speak one language, though as to whether it is anything at all like the 'English' we speak now is another matter, it will probs be a mishmash of whatever is useful, after all, that's exactly how all languages have grown over the last several thousand years
Flipside