My students, at ALL levels, have a very common habit of simply answering "No" when asked "What?" by a teacher.
For example, the student will raise her hand, and the teacher will say, "Yes, Gayeong?" and the student will simply reply "No." This is just a direct translation of how Koreans express the concept expressed more colloquially in English with responses like "Nevermind" or "Nothing" or "I forgot what I was gonna say."
I try very hard to convince the students that just saying "No" in English in this pragmatic context doesn't work. It comes across as incoherent at best and rude at worst. I don't know why this is – it's just the way English pragmatics works, I guess.
So I felt a huge victory last night when Gayeong raised her hand and yelled out, "Teacher!" as students do, in Korea (another mismatch on pragmatics, but that's a different battle). I said to her, "What?" and without missing a beat, and with perfect intonation and grammar, she said, "Oh. I forgot what I was gonna say."
I was so impressed. It's been at least a year with that class, since I first said, please don't just say "No" when you don't want to answer my question "What?"
[daily log: what? no. walking, 7.5km]