commentator vs lector

commentator

noun
  • A medieval legal scholar who authored prose commentaries on civil law; (specifically) a member of a comparatively innovative 14th-century school of jurisprudence, typically distinguished from the earlier glossators. 

  • A person who comments; especially someone who is paid to give his/her opinions in the media about current affairs, sports, etc. 

lector

noun
  • A public lecturer or reader at some universities. 

  • A person doing voice-over translation of foreign films, especially in Eastern European countries. 

  • A lay person who reads aloud certain religious texts in a church service. 

  • A person who reads aloud to workers to entertain them, appointed by a trade union. 

verb
  • To do a voice-over translation of a film. 

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