Idea for an activity:
Like the mirror game, where you mimic the other person's movements in real time, in this game one person speaks, one sentence at a time, and the listener repeats verbatim what the speaker said, as close to simultaneously as possible.
Maybe start with the mirror game, as a warm-up, then introduce speech. (One might also show the great mirror sequence in Duck Soup.)
The idea is to make the speaker, listener, and referee more attentive to the exact way they are expressing themselves.