Possible Clues:

• Barracked
• Made sound of snake
• They certainly did not applaud his backward boy
• 'Listen,' you say. 'It sounded angry'
• Made a snakelike sound
• Said 'Be quiet!' when the audience showed its disapproval
• Said menacingly 'Is hiding in the derelict shed'
• Jeered (6)
• The ones she'd contrived to trap sounded angry
• Expressed scorn