mouthpiece vs point person

mouthpiece

noun
  • A spokesman; one who speaks on behalf of someone else. 

  • The part of a wind instrument that is held in or against the mouth. 

  • A lawyer for the defense. 

  • The part of a telephone that is held close to the mouth. 

point person

noun
  • The person in the most prominent position on something, such as a spokesperson or manager. 

  • One who goes ahead of a group in order to indicate the direction in which it should move. 

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