explainer vs translator

explainer

noun
  • A guide that explains a topic. 

translator

noun
  • A person who converts speech, text, film, or other material into a different language. (Contrasted with interpreter.) 

  • One that makes a new version of a source material in a different language or format. 

  • A computer program that translates something from one language to another using machine translation. 

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