Related Clues:

• "I'm impressed!"
• Crowd's gasp
• Sound of amazement
• 'Isn't that pretty!'
• Fireworks sound
• "Amazing!"
• Awesome!
• ___-la
• Expression of disbelief
• Start of a lilt, perhaps
• Backup singer's syllable
• ___ -la-la
• Awed one's reaction
• -- la la
• Start of a musical refrain