Asklemmy

There weren't many other kids who spoke Cantonese at my school (a couple, but not a lot), but I learned to be paranoid after one incident in English class.

My teacher at the time was like the most stereotypical looking white guy you could imagine. Being a school in a big city, we had a pretty diverse population of students, and in this particular class there were two boys who were friends and would often goof off between themselves in Spanish.

One day about 2/3 of the way through the school year, I have no idea what one of the two boys must have said, but Mr. "Grew up on a farm in Ohio" quickly turned around from the board and interjected in the most native-sounding Spanish my untrained ears could parse. That immediately put the fear of god in them—in all of us, really—to suddenly realize that he had been listening to and understood everything they were saying from the very beginning of the school year, and had just not bothered to say anything until then. I think we were basically an English-only English class from that point on.

Between that experience and other stories I've read online, I've learned to never, ever assume that someone doesn't understand what you're saying in another language. You never know what unlikely language someone picked up because they had a pen pal or their SO is from another country or they lived/worked abroad for a while. Even then, since it's so easy these days for anyone to subtly pull out a smartphone and let Google Translate provide the gist of what is being said with relative accuracy, you should never say out loud something you don't want someone else to hear.

Edit: a word