Possible Clues:

• Watching what's been said when excluded from The Hearing following the mouthy movement
• Silently getting message at the front to arrest one pair
• By way of communication it's quite unsound
• Interpretation by following mouth movements
• Seeing what's said of the pig Ireland made
• Gin and pie made with lard will help conversation
• Genial drip (anag.)
• Looking at the address
• Hearing by seeing?
• Interpreting speech without hearing it