double-tongued vs multilingual

double-tongued

adj
  • Saying one thing to one person and something different to another; double talking; deceitful in speech. 

multilingual

adj
  • Of, relating to, or involving multiple languages. 

  • able to communicate in a number of languages. 

noun
  • a polyglot 

How often have the words double-tongued and multilingual occurred in a corpus of books? (source: Google Ngram Viewer )