Possible Clues:

• 'I'm not listening ...'
• ''Deck the Halls'' sequence
• Singing syllables
• Repeated part of 'Deck the Halls'
• "Deck the Halls" ending
• ''I don't remember the words ...''
• Refrain sequence
• "I don't remember the words ..."
• [I can't remember the words to this song]
• 'Deck the Halls' snippet