The quietest guest may need an opening, not an announcement that they are quiet.

Naming someone’s silence puts them on stage at the exact moment they least want to be there. Saying you have been very quiet tonight asks them to account for themselves in front of everyone. What usually helps is smaller: a question with an easy answer, a place to enter that does not require a performance.

Sit near them rather than across from them. Ask something specific and low-stakes, then let the conversation carry on around the answer so it does not become a spotlight. Most quiet people are willing to speak; they are just waiting for a door that is not a stage.