Possible Clues:

• Button pressed for silence
• Like Avoxes in 'The Hunger Games,' because the government cut their tongues out
• Horn accessory
• Kill the sound, like I bet you wish you could do with someone talking like a 41-Across
• Eliminate sound
• Horn blower's accessory
• Uncommunicative
• Deaden sound of
• Voiceless
• Cello attachment near the bridge