Capn Bloggs,
I'm not disputing the first part of your post in any way. I'm not advocating cutting back on SA! What I'm saying is that to not provide ATC in french to a french pilot (or in spanish to a spanish pilot) has a more profound effect on safety than the reduced situational awareness you get from the double-dutch.
I work in a bilingual terminal, as you might have guessed. I get plenty of pilots practicing their English and it is certainly encouraged as speaking two languages will always be better than just one (even if that one language is English
). However, if that practice becomes an obstacle to controller-pilot communication then I speak to them in French. A clear communication channel between controllers and pilot trumps pilot-airspace-SA everytime.
For the second part of your post, I still say that bubbers44 was able to maintain his situational awareness despite the language barrier. In fact, had he heard it in english, he might have become complacent as we don't know if the other traffic didn't just bust a correctly read-back altitude.
Cheers!