insist vs speak out

insist

verb
  • To demand continually that something happen or be done; to reiterate a demand despite requests to abandon it. 

  • To hold up a claim emphatically. 

speak out

verb
  • To assert or promote one's opinion; to make one's thoughts known. 

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