Look at this three predictions about the future of English:
1. English will become dominant lenguage.
2. World will become multilingual.
3. English will dissappear.
Nowaday English is being used like an universal language, a few countries have the name of their streets in their language and also translate that name in English; American Economy is rising and for a business relationship with people of this country the interested has to speak the language or at least understand it; English an easy language to learn; in Mexico there are more oportunities to find a job if you know the language; most of the software are in English.
So in my opinion the most plausible prediction is the number 1.