megaphone vs spokesman

megaphone

noun
  • Mouthpiece or promoter; one who speaks for or publicizes on behalf of another. 

  • A portable, usually hand-held, funnel-shaped device that is used to amplify a person’s natural voice toward a targeted direction. 

  • A cytotoxic neolignan obtained from the laurel Aniba megaphylla. 

verb
  • To use a megaphone; to speak through a megaphone. 

spokesman

noun
  • One who speaks as the voice of another person or a group of people. 

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