clack vs falsetto

clack

verb
  • To chatter or babble; to utter rapidly without consideration. 

  • To cause to make a sudden, sharp noise, or succession of noises; to click. 

  • To make a sudden, sharp noise, or succession of noises; to click. 

  • To cut the sheep's mark off (wool), to make the wool weigh less and thus yield less duty. 

noun
  • Chatter; prattle. 

  • The tongue. 

  • An abrupt, sharp sound, especially one made by two hard objects colliding repetitively; a sound midway between a click and a clunk. 

  • Anything that causes a clacking noise, such as the clapper of a mill, or a clack valve. 

falsetto

verb
  • To sing or utter in falsetto. 

noun
  • A person who sings in falsetto. 

  • The "false" (singing) voice in any human, usually airy and lacking a purity of vowels; created by utilizing the next highest vocal folds above those used for speech and normal range singing. It is commonly confused with the head voice register. 

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