apostrophe vs echoism

apostrophe

noun
  • The text character ’, which serves as a punctuation mark in various languages and as a diacritical mark in certain rare contexts. 

  • A sudden exclamatory piece of dialogue addressed to someone or something, especially absent. 

echoism

noun
  • The practice of creating words or language by imitating sounds from the environment. 

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