Squawk, easy to blame and redefine who was wrong during these accidents.
Yet in CDG, had they been using a common language (English in that instance) the chances of an accident occuring would be slim to none.
The other examples provided on this thread about Germany or Canada are different IMHO. I do not remember any instance in my time in Germany, where I was confronted to ANYONE not speaking or understanding English, even outside aviation. I Canada, some hardcore French speakers want to keep French as an official language for aviation, based on historical pride and claims of cultural identity. I have yet to meet any Canadian (or Quebecois, for that matter) that is unable to read, speak and understand English.
Now the French are a different breed. It may be more pronounced in the previous generation, but they are reluctant to speak English for a very good reason: THEY CAN'T. Listen to the majority of AF flights abroad, their level of English is appalling, I know a significant number of AF pilots who readily admit that they have a problem with English in the cockpit and many do struggle on international flights to keep up with ATC. Just read the CVR transcript of AF447, it'll show an example at work, where numerous times neither pilot understands who ATC is talking to, or misread instructions. Sad coincidence it was this particular flight, just the latest factual example I came across to read.
Now if Spain makes the move, one can hope others will follow their example, but I would not count on the French, where pride, arrogance and ignorance will prevail against common sense, improved comms with international flights, and improved safety for all.