monotone vs sing-song

monotone

noun
  • A single unvaried tone of speech or a sound. 

  • A piece of writing in one strain throughout. 

adj
  • Being, or having the salient properties of, a monotone function. 

  • Having a single unvaried pitch. 

verb
  • To speak in a monotone. 

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. 

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