dialectical vs discursory

dialectical

adj
  • Of, or pertaining to dialectic; (in philosophy) logically reasoned through the exchange of opposing ideas. 

  • Synonym of dialectal (“of, or peculiar to a dialect”) 

discursory

adj
  • argumentative; discursive; reasoning 

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