At Big Airways in the UK there are several planned emergency briefings on a pre recorded announcement Machine (PRAM) the idea being that the crew are carrying out their duties and demonstrations whilst this announcement is played. From memory there is one for an emergency landing and one for ditching which are operated by the CC. In a decompression there is one that is played automatically when the masks are deployed at Cabin alt 14000'.
In unplanned emergencies it is much a case of shouting the basics as the PA's come from the Flight Deck - 'This is the captain, this is an emergency BRACE BRACE!"