mouthing vs pronunciation

mouthing

noun
  • The act of forming a shape with the mouth, especially as part of sign language. 

  • Ranting; passionate speech devoid of meaning. 

pronunciation

noun
  • The act of pronouncing or uttering a vocable. 

  • The formal or informal way in which a word is made to sound when spoken. 

  • The way in which the words of a language are made to sound when speaking. 

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