DEAR GENIUS, IF YOU WEREN'T POLYLINGUAL YOU WOULDN'T BE ABLE TO TELL WHICH ONE OF THE PEOPLE IN THE ROOM WITH YOU, WHO SPEAK TO YOU FOR SEVERAL MINUTES EACH, IN DIFFERENT LANGUAGES FROM ONE ANOTHER, AND NOT IN YOUR PRIMARY LANGUAGE, EVEN IF YOU WERE BLIND, WHICH ONE IS SPEAKING CHINESE, WHICH RUSSIAN, WHICH FRENCH, WHICH GERMAN, AND YET YOU WOULD EASILY BE ABLE TO TELL, HUH?