We practice calling 911 many times during the year. My students LOVE acting out scenes of an emergency. They literally will lay on the floor and look unconscious while the "call" is happening. I have a student in my class who is verbal but very hard to understand. We practice just getting out one or two words (mom sick, dad hurt) and than answer yes or no to the dispatcher (me) questions.
Here is a worksheet that can be used before role play.