When a Spanish player, a Swedish player and a Dutch referee are having a discussion, what language are they using?

English!

I sometimes think they have a language all of their own...

But usually English

Most of the time, it's English, but other times, they can use sign language.

For example, when a Brazilian joins an English club, he obviously won't know perfect English, so he'll make a gesture to his teammates, or to the ref. Like if a corner is given, and the Brazilian wants to take it, he'll point to himself, then to the flag, letting his teammates know he'll take the corner, since he hasn't learned the language yet, and can't say "I'll take it".

That's what I've been told anyway.