inner ear vs listening

inner ear

noun
  • Mind's ear. 

  • The portion of the ear located within the temporal bone which includes the semicircular canals, vestibule, and cochlea and is responsible for hearing and balance. 

listening

noun
  • Action of the verb listening 

  • Skill or ability of perceiving spoken language. 

  • An educational exercise involving listening 

adj
  • Of an action that is performed with caution and attention to sounds. 

  • Of something that is used in order to hear or to improve the ability to hear. 

  • Of something or someone that listens. 

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