At a tertiary institution in Hong Kong, a foreign teacher is lecturing to a class of students, who listen attentively, occasionally commenting to each other in Cantonese on what the teacher has said. The teacher, disturbed by the talking, stops and waits for the students to stop. The students, sensing the teacher's discomfort, become silent, and the teacher resumes lecturing. Gradually, the students learn that the teacher expects them to be silent when she is lecturing. At the end of the lecture, the teacher asks whether there are questions. One student asks a question, and, as the teacher responds, the other students start talking among themselves. Soon it becomes noisy enough that the teacher either has to move toward the student in order to continue the discourse or ask the other students to be quiet. In either case, it is not long before students begin to ask whether they are permitted to leave. The teacher must then decide whether the class is over and if so, either give nonverbal permission and continue talking, or cut off her conversation at least momentarily to announce that the class is dismissed. If not, she may hurriedly give instructions regarding the assignment for the next class. She cannot help feeling that the students are being rude or showing lack of interest in the class. She may feel that she is wasting her breath if one student has raised an important question and the others are not listening to her response.

(SCOLLON, S. Not to waste words or students. In Culture in Second Teaching and Learning. 6ed. Cambridge: C.U.P., Applied Linguistics Series, 2006.)