conversation vs private conversation

conversation

noun
  • Expression and exchange of individual ideas through talking with other people; also, a set instance or occasion of such talking. 

  • The protocol-based interaction between systems processing a transaction. 

  • The back-and-forth play of the blades in a bout. 

verb
  • To engage in conversation (with). 

private conversation

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