hearken vs listen

hearken

verb
  • To listen; to attend or give heed to what is uttered; to hear with attention, compliance, or obedience. 

  • To hear (something) with attention; to have regard to (something). 

listen

verb
  • To accept advice or obey instruction; to agree or assent. 

  • To pay attention to a sound or speech. 

  • To expect or wait for a sound, such as a signal. 

noun
  • An instance of listening. 

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