interject vs intersperse

interject

verb
  • To insert something between other things. 

  • To say as an interruption or aside. 

  • To interpose oneself; to intervene. 

intersperse

verb
  • To scatter or insert something into or among other things. 

  • To diversify by placing or inserting other things among something. 

  • To mix two things irregularly, placing things of one kind among things of other. 

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