en_tn_condensed/act/02/03.md

There appeared to them tongues like fire

These might have been something that looked like tongues or like fire, not actual tongues or fire. Possible meanings are 1) tongues that looked like they were made of fire or 2) small flames of fire that looked like tongues. When fire burns in a small space, such as on a lamp, the flame can be shaped like a tongue. (See: rc://en/ta/man/jit/figs-simile)

that were distributed, and they sat upon each one of them

This means that the "tongues like fire" spread out so that there was one on each person.