mouthing vs pronouncement

mouthing

noun
  • Ranting; passionate speech devoid of meaning. 

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

pronouncement

noun
  • An utterance. 

  • An official public announcement. 

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