lingual vs unwritten

lingual

adj
  • Related to language or linguistics. 

  • Related to, near, or on the side toward the tongue. 

  • Articulated with the tongue. 

noun
  • A sound articulated with the tongue. 

unwritten

adj
  • Implicit or understood but not formally articulated. 

  • Not written. 

  • Oral or otherwise communicated without writing. 

  • Containing no writing; blank. 

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