well... I read a great part of this thread, and then I got sick... tired... weary...
It sometimes comes to my mind that the crux of the matter is not so much "let English be the one and unique langage in aviation for safer skies"... than "let us kill those stinky French frog eaters !"...
and it seems to be recurrent on pprune... it's a shame...
When it comes to bilingual airspace, it always comes back to French-English airspace, and then ends up in "French controllers' deplorable level of English..."... strange that you rarely write about the French Canadian airspace... where both language are also used...
I agree that one language is better, I'm in favour of that, although I'm an ATCO at CDG (please, don't puke on my shoes thanks...
), especially on tower and ground frequencies.
But then I regret that continuing French bashing and narrow mindedness....
Let me remind you that when I read that "the English invented av iation"... I kind of laugh because the Wrights were American... and Clément Ader invented the first aeroplane, which he named "avion"