know vs speak

know

verb
  • To be or become aware or cognizant. 

  • To perceive the truth or factuality of; to be certain of or that. 

  • To experience. 

  • To understand or have a grasp of through experience or study. 

  • To be able to play or perform (a song or other piece of music). 

  • To be acquainted or familiar with; to have encountered. 

  • To be aware of; to be cognizant of. 

  • To recognize as the same (as someone or something previously encountered) after an absence or change. 

  • To have knowledge; to have information, be informed. 

noun
  • Knowledge; the state of knowing. 

  • Knowledge; the state of knowing; now confined to the fixed phrase ‘in the know’ 

speak

verb
  • To communicate (some fact or feeling); to bespeak, to indicate. 

  • To communicate with one's voice, to say words out loud. 

  • To understand (as though it were a language). 

  • To have a conversation. 

  • To utter. 

  • To produce a sound; to sound. 

  • To be able to communicate in a language. 

  • Of a bird, to be able to vocally reproduce words or phrases from a human language. 

  • To deliver a message to a group; to deliver a speech. 

  • To be able to communicate in the manner of specialists in a field. 

  • To communicate or converse by some means other than orally, such as writing or facial expressions. 

noun
  • Speech, conversation. 

  • language, jargon, or terminology used uniquely in a particular environment or group. 

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