particularize vs severalize

particularize

verb
  • To differentiate, make distinct from others. 

  • To make particular, as opposed to general; to restrict to a specific or individual case, class etc.; to single out. 

  • To be specific about (individual instances); to go into detail (about), to specify. 

severalize

verb
  • To distinguish; to make or treat as several. 

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