Quiet in class doesn’t mean nothing is happening. Some people need to think before they talk.

Speed of speech is not speed of thought. Some people assemble an answer out loud and some need the sentence finished before they will say it, and classrooms are built for the first kind, which makes the second look absent. Nothing has stopped happening behind a quiet face. The thinking is being done before the talking rather than during it.

If that is you, use writing where speech is slow, and bring one prepared sentence rather than improvising three. One good line beats putting your hand up early. And if you are the quick talker, leave a gap after your question, because somebody is still building.