Demosthenic vs plain-spoken

Demosthenic

adj
  • Pertaining to or characteristic of Demosthenes, a celebrated Athenian orator (384-322, B.C.), especially famous for his "Phillippics," or orations delivered against the encroachments of Philip, king of Macedon. 

plain-spoken

adj
  • Speaking in an honest, forthright manner. 

How often have the words Demosthenic and plain-spoken occurred in a corpus of books? (source: Google Ngram Viewer )