Possible Clues:

• Remarkably, the edge comes in the middle
• Make Father or Father in this?
• Dramatists' devices
• They may be said to start with, but only in play
• Words spoken from corner of mouth.
• Words spoken in undertones
• Stage-whispers
• Seems a team is getting to the stage of being spoken, perhaps
• Said in play that that's like a bad time for Caesar
• They're on the stage, in a manner of speaking