Possible Clues:

• Speak hypnotically
• Pray aloud, perhaps
• Recite without inflection
• Chant monotonously
• It's not in the big bad one that one may sing, by the sound of it
• Utter dully
• To get in nine and sing (6)
• One might make a song, but not a dance, with the tin that's broken
• Sing in a singular way in the end
• Are nine about to sing like that?