expound vs interpret

expound

verb
  • To set out the meaning of; to explain or discuss at length 

  • To make a statement, especially at length. 

interpret

verb
  • To explain or tell the meaning of; to translate orally into intelligible or familiar language or terms. applied especially to language, but also to dreams, signs, conduct, mysteries, etc. 

  • To convey what a user of one language is saying or signing, in real time or shortly after that person has finished communicating, to a user of a different language 

  • To analyse or execute (a program) by reading the instructions as they are encountered, rather than compiling in advance. 

  • To apprehend and represent by means of art; to show by illustrative representation 

  • To decode the meaning of a topic and then act, whether to continue researching the topic, follow through, act in opposition, or further the understanding through sharing an interpretation. 

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