Danil knows LanguageA.
LanguageA is a universal language If a universal language exists, then for every two people if they both know the same universal language they can communicate. Katya cannot communicate with Danil. Katya knows LanguageA. 
UniversalLanguage(languageA) ∀x ∀y (∃z (Know(x, z) ∧ Know(y, z) ∧ UniversalLanguage(z)) → Communicate(x, y)) Know(katya, languageA) ¬Communicate(katya, danil)