Languages

So its well into the the second games of the round robin and there have been many great goals, set ups and saves. I have had this random question though in my mind what language do they referee the game? I mean every 4 years the host country changes (Germany, South Korea, France have been the latest three), and the players come from all different countries and speak tons of random languages and dilalects. So what happens in a match if you are being reffed in a language you don't understand? How do you dispute a call? Do the refs need to be fluent in each team's national language?