I always see in TV referees communicating with the players in international football matches(both club and national competitions). It seems to be universal: not only in European matches, but also in Asian matches and World Cup etc. However something I don't really get is how are they supposed to communicate at all if they don't speak the same language.
I can only suppose that in this case, there exists a default lingua franca for communication, for example English, and all players more or less understand some basics of this language. (which would not be easy for professional sports players, and it's even more amazing that they can seem able to talk incessantly). If so, is it somehow specified as a rule, or just more of a custom?
Or, as an alternative, is there actually only the captain, or the few players who share languages in common with the referee doing the talking, while others express themselves more by body expressions and translation through the captain etc.?
Are international football referees (supposed to be & in reality) multilingual?