Who don't know how to sing? Say, I've got a voice like a Nightingale. Watch me knock off this cadenza.
8 seconds sound clip from the Palooka (1934) movie soundboard.
You can hear this line at 00:53:57 in the Blu-ray version of the movie.
Quote context
[...]
- Now we'll drink to Mother Hubbard, Mother McCree, and Mother Goose. Hooray!
- That was a pip. That was a pip.
- Say, that makes 12 bottles of champagne, and 42 mothers.
- Why, the sentiment is so beautiful, it makes me want to sing.
- Oh, please don't sing. You don't know how to sing.
- M is for a million things you gave me, O is for...
- Out!
- I'm Knobby Walsh, the champ's manager.
- Well, I told you a dozen times before you can't sing in here.
- Hey, when a waltz makes up his mind to sing, he's going to sing.
[...]