The Penny Serenade song was written by Arthur William Halifax and Melle Weersma and recorded in New York February 14, 1939 by Guy Lombardo and His Royal Canadians.
These are the lyrics of the Penny Serenade Song:
Once I strayed 'neath the window of a lovely seņorita
And she smiled while I softly played my Penny Serenade
Si, si, si, you can hear it for a penny
Si, si, si, just a Penny Serenade
In her eyes shone the tender dawn of love and sweet surrender
As for me, in my heart I played a lover's serenade
Si, si, si, hear my love song for a penny
Si, si, si, just a Penny Serenade
For that night so divine she was mine, no word had been spoken
When I woke from my dream she was gone, my poor heart was broken
Still I pray that wherever she may be she will remember
In her heart she will always hear my Penny Serenade
Si, si, si, hear my love song for a penny
Si, si, si, just a Penny Serenade
In the movie, songs mark episodes in the action from records from their collection -- the title refers to a song of the same name.