open one's mouth vs oration

open one's mouth

verb
  • to speak 

oration

verb
  • To deliver an oration; to speak. 

noun
  • A specific form of short, solemn prayer said by the president of the liturgical celebration on behalf of the people. 

  • A formal, often ceremonial speech. 

  • A lengthy speech or argument in a private setting. 

How often have the words open one's mouth and oration occurred in a corpus of books? (source: Google Ngram Viewer )