Silence does not always mark wisdom.

Quiet can mean depth, and it can equally mean having nothing to say, or being unwilling to take a position, or waiting to see which way the room goes. The listener cannot tell the difference, which is why silence is so often over-credited. Someone with a reputation for saying little is sometimes just someone who has never been tested.

Do not mistake reticence for judgement when assessing people, your own included. Ask the quiet person directly what they think, since some are genuinely worth hearing and some have been coasting on the mystery. And when you are the one holding back, check which of the reasons is actually yours.