You lose situational awareness because of a foreign language?
No, but I don't gain it. Therefore, not having as much SA as I could have IF everybody was speaking the same language.
did not maintain sterile cockpit
This would only have made a difference IF everybody had been using the same language. The ultimate difference between not hearing a transmission, hearing only half of a transmission or not understanding a transmission is..........
nothing.
Besides, how do you know that critical information was transmitted, if you do not understand French?
That's his point.
I have flown in dual-language environments where I did not understand the non-English language and I didn't feel my safety compromised in any way
How would you know? Answer this truthfully - How would you know that you hadn't missed a vital piece of information if it was transmitted in a language that you did not understand? Don't bother actually because it'll be nonsense. I'll answer for you. YOU WOULDN'T.
a person only capable of speaking one language is a monoglot
Thanks for the definition but there really is no need to state the bleeding obvious.