Having English as the official "language of the skies" means that the Russians can understand the Japanese, that the Iranians can converse with the Brazilians and the Indians can talk to the Koreans.
+1. Add the fact that basic english is easy to learn and speak...
AFAIK you can fly IFR without an english radio licence in France, guess thats a 'La Grande Nation' traditional thing...? I Germany you need an english RTL licence before you´re allowed to take IFR training. How the french/chinese/russion/spanish ATC controller maintain their awareness when switching back and forth between languages in high stress situations is a miracle to me...