mention vs specialize

mention

verb
  • To make a short reference to something. 

  • To utter a word or expression in order to refer to the expression itself, as opposed to its usual referent. 

noun
  • A speaking or notice of anything, usually in a brief or cursory manner. Used especially in the phrase make mention of. 

  • A social media feed, a list of replies or posts mentioning a person. 

specialize

verb
  • To specify: to mention specifically. 

  • To become distinct or separate from what is common 

  • To focus one's study upon a particular skill, field, topic, or genre. 

  • To make distinct or separate due to form or function. 

  • To narrow in scope. 

  • To be known or notorious for some specialty. 

  • To focus one's business upon a particular item or service. 

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