sing-song vs yodel

sing-song

noun
  • A kind of verse with a simple, song-like rhythm. 

  • An informal gathering involving group singing. 

adj
  • Like a piece of sing-song; simple and melodic, song-like. 

yodel

noun
  • A song incorporating yodelling. 

  • An act of yodelling. 

verb
  • To sing (a song) in such a way that the voice fluctuates rapidly between the normal chest voice and falsetto. 

How often have the words sing-song and yodel occurred in a corpus of books? (source: Google Ngram Viewer )