I think there's an interesting middle ground in tibetian buddhism, with 3 year retreats that are done in groups, but in silence. i think i read some of them don't feel alone this way.
Do they communicate still? Monks in middle-age Britain who lived in silent(-ish) orders used sign-languages, eg for meal times when they were supposed to be listening to the readings.
A vow of silence when you still "talk" with sign seems a bit of a cheat to me.
I think there may be something similar for practical communication.As for whether it's a cheat ? IDK, but the goals there aren't "be solitary", but certain type of personal development, and relatively i think tibetian buddhists are good at it.
