cronk vs mumble

cronk

noun
  • The honking sound of a goose. 

  • A hill or barrow. 

verb
  • To honk like a goose. 

mumble

noun
  • A quiet or unintelligible vocalization; a low tone of voice. 

verb
  • To speak unintelligibly or inaudibly; to fail to articulate. 

  • To chew something gently with closed lips. 

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