In group projects, the quiet one has often noticed the problem everyone else is talking over.

Talking and noticing draw on different energy, and the person doing least of the first is often doing most of the second. Quiet people have had the whole meeting to watch, so the flaw in the plan has usually registered with them before anybody else, and it stays unsaid because no gap opens up to say it in. Loud rooms lose information. Somebody has to make the room.

Ask the quietest person in your group what they think, by name and directly. Then wait through the silence instead of filling it.