mouthpiece vs telephony

mouthpiece

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

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

  • A lawyer for the defense. 

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

telephony

noun
  • The study and application of telephone technology. 

  • The act of sound transmission via the electromagnetic spectrum. 

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