discourse vs sound off

discourse

verb
  • To engage in discussion or conversation; to converse. 

  • To exercise reason; to employ the mind in judging and inferring; to reason. 

  • To write or speak formally and at length. 

noun
  • Expression in words, either speech or writing. 

  • A formal lengthy exposition of some subject, either spoken or written. 

  • An institutionalized way of thinking, a social boundary defining what can be said about a specific topic (after Michel Foucault). 

  • Any rational expression, reason. 

sound off

verb
  • To hold forth about something in an opinionated manner. 

  • Command instructing a person to confirm that they are present or that some other objective has been met. 

  • Command instructing a person to speak up or acknowledge something. 

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