[antognini]

The Carthusian monks are probably the closest to hermits in the Catholic Church. They spend almost all of their time alone in their cells. Although they don't take a formal vow of silence, unnecessary talking is discouraged. The one exception is that they take a communal walk on Mondays where they're allowed to talk about whatever they want.

(As an aside, for anyone interested in their lives, there's a great documentary called Into Great Silence. It's long and has no narration, but there's a great scene at the very end where it shows the monks on one of their Monday walks going sledding in the Alps.)