Possible Clues:

• "Well, --- -di-dah!"
• ''Well ___-di-dah ...''
• ____de dah
• "Well --- -di-dah"
• "Well, __-de-dah"
• Musical syllable
• "Well, ___-di-freakin'-dah!"
• ''Well ___-di-dah''
• Sixth note of major scale
• "Well, ___-di- dah!"