descant vs ditty

descant

verb
  • To sing or play a descant. 

  • To discuss at length. 

noun
  • A lengthy discourse on a subject. 

  • A counterpoint melody sung or played above the theme. 

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 descant and ditty occurred in a corpus of books? (source: Google Ngram Viewer )