incomprehensibility vs intelligibility

incomprehensibility

noun
  • Something that cannot be understood. 

  • The condition of being incomprehensible. 

intelligibility

noun
  • The quality of recorded speech of every word being understandable. 

  • That which is intelligible; the degree to which something is intelligible. 

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