chirl vs ditty

chirl

verb
  • To emit a low sound; to warble. 

noun
  • A kind of musical warble. 

ditty

verb
  • To sing; to warble a little tune. 

noun
  • A saying or utterance, especially one that is short and frequently repeated. 

  • A short, simple verse or song. 

How often have the words chirl and ditty occurred in a corpus of books? (source: Google Ngram Viewer )