Wasn't it the french president who said "every frenchman has a god given right to speak french when in france"? This was a well constructed argument when the Air France pilots started refusing to reply in french to a french controller, when given an instruction in french.
The result was several near misses at CDG (which I suspect would have killed more than the 9 in your local field). I personally saw one of these, AF lined up with an Aeroflot on finals at 100-200'. Thanks to the quick reactions of the IL76 pilots they got away with it. The Aeroflot crew then ignored all subsequent transmissions from tower, flew a tight circuit and landed.
There is no substitute for looking out the darn window no matter what language you're using. Personally I enjoy flying non-radio. It avoids having to speak to arrogant people - like french controllers.