intelligibility vs persuasiveness

intelligibility

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

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

persuasiveness

noun
  • The capability of a person or argument to convince or persuade someone to accept a desired way of thinking. 

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