unmentioned vs unvoiced

unmentioned

adj
  • Not mentioned. 

unvoiced

adj
  • Not spoken or expressed. 

  • Spoken without vibration of the vocal chords. 

  • Of an IRC user: not granted voice privileges. 

  • That does not contain voice. 

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