bemoan vs falsetto

bemoan

verb
  • To moan or complain about (something). 

  • To be dismayed or worried about (someone), particularly because of their situation or what has happened to them. 

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 bemoan and falsetto occurred in a corpus of books? (source: Google Ngram Viewer )