mouthing vs ventilation

mouthing

noun
  • Ranting; passionate speech devoid of meaning. 

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

ventilation

noun
  • An exchange of views during a discussion. 

  • The bodily process of breathing; the inhalation of air to provide oxygen, and the exhalation of spent air to remove carbon dioxide. 

  • The mechanical system used to assist breathing. 

  • The replacement of stale or noxious air with fresh. 

  • The public exposure of an issue or topic. 

  • The mechanical system used to circulate and replace air. 

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