A familiar chorus becomes communal when strangers stop needing to read the words.

Knowing something by heart frees you to notice everyone else knowing it too. While people are reading, attention stays on the page and each person is alone with it. Once the words are internal, heads come up and the room becomes one thing. Shared memory is what turns a crowd into company.

Learn the words to something your people sing, whether a hymn, an anthem or a birthday round. It costs one evening at most. Then you get to spend the occasion looking at faces instead of at a sheet of paper.