Talking and listening compete for the same minutes. Someone who is not filling the room has been taking it in: who said what, who went tense, what was avoided. They often hold the clearest picture of a situation and are the last to be asked for it. Quiet reads as having nothing to say, when usually it is the opposite.

In your next group thing, ask the person who has not spoken what they think, and then actually wait. Ten seconds of silence is uncomfortable and usually productive. If you are the quiet one, pick one moment to say the thing you have been noticing all along.