polylingual vs two-tongued

polylingual

adj
  • of or pertaining to multiple languages; multilingual 

  • able to use multiple languages 

two-tongued

adj
  • Possessing the ability to speak two languages; synonym of bilingual. 

  • Deceitful; lying; two-faced. 

  • Having two tongues; double-tongued. 

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