http://en.wikipedia.org/wiki/Mairzy_Doats
One of the writers, Milton Drake, says the song is based on an English nursery rhyme. Drake says the idea came to him when his four-year-old daughter came home singing the English rhyme which starts “Cowzy tweet and sowzy tweet and liddle sharksy doisters.” (Cows eat wheat and sows eat wheat and little sharks eat oysters.)
Squee!