This happened when I was in high school.
English Teacher: Class, spell "KEYFYU."
Class: (utterly dumbfounded).
In my group of friends, we had specialties. One was really good at Physics. My specialty was English and so when dead silence met my teacher's inquiry, my friends all looked at me as if I were the day's savior.
Friend 1: Lai, what's "keyfyu?"
Friend 2: (acting as a moral booster). Go go go, answer it!
Me: I don't know what the word means. Maybe it's a French word, judging from the way she pronounced it.
Friend 2: Come on, think. You can do it!
Me: Hey, zip it! I haven't taken any French lessons and the only French words I know are mademoiselle, oui, non, moi and merci so don't go offering me to her like a lamb to slaughter as I absolutely have no idea what "keyfyu" means.
Then, as it was blatantly obvious that no one among her "special science curriculum" students knew what keyfyu means, our teacher heaved such a loud sigh of resignation.
Teacher: (writing the word in the blackboard).
Amidst a collective ahhs and ohhs, the whole class then said in the loudest of voices:
And then we had the satisfaction of seeing our teacher's face go beet red.
And thus concludes our "French" lesson for today. He he he!