creak vs falsetto

creak

noun
  • The sound produced by anything that creaks; a creaking. 

verb
  • To make a prolonged sharp grating or squeaking sound, as by the friction of hard substances. 

  • To produce a creaking sound with. 

  • To suffer from strain or old age. 

falsetto

noun
  • 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. 

  • A person who sings in falsetto. 

verb
  • To sing or utter in falsetto. 

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