As a child I was confused by deodorant ads on tv. They depicted people putting deodorant on the insides of their forearms, yet somehow I knew that deodorant (although I did not need it yet) was to be applied on the armpits, what the ads called, ambiguously, "underarms." Where were the "underarms," really? That was a plausible name for the forearms as well as for the pits themselves. Eventually I figured that out.
I was a Spanish professor already, and was translating a book by Lola Velasco. I translated the word "cometa" as "comet," when of course it means "kite." The difference is between "el cometa" and "la cometa." Just like "la frente" means the forehead and "el frente" is the front in a war, or "el corte" is a cut and "la corte" a court. I should have looked at the picture of kites that Lola drew in her book for me. (Kites not the bird but the flying diamond-shape toy.) Luckily I didn't publish anything from this translation.
A colleague, also a specialist in poetry, and a native speaker of English, asked me how to pronounce the word "prosody."
To be continued, perhaps...