en_tn_condensed/1co/14/27.md

speaks in a tongue

Here "tongue" represents a language. Alternate translation: "speaks in a different languages" (See: rc://en/ta/man/translate/figs-metonymy)

and each one in turn

"and they should speak one after another" or "and they should speak one at a time"

interpret what is said

This can be stated in active form. Alternate translation: "interpret what they said" (See: rc://en/ta/man/translate/figs-activepassive)

interpret

This means to listen to what someone says in one language and use another language to tell people what that person is saying.