The Brazilian referee and his assistants who will take charge of the England-United States match at the World Cup have been studying English-language obscenities the players might use.
Carlos Simon will referee Saturday's match in Rustenburg, assisted by Roberto Braatz and Altemir Hausmann, and wants to ensure players can't get away with abuse.
"We have to learn what kind of words the players say," Hausmann told Brazilian broadcaster Globo Sport. "All players swear and we know we will hear a few."
Braatz says they aren't learning them in "11 different languages but at least we have to know the swear words in English."
FIFA denied reports that match officials have been given lists of swear words to listen out for, but did say proficiency in English was a requirement for referees and assistants working at the World Cup.
In addition, refereeing officials had briefed all teams in the lead-up to the event about the rules, including the potential for players to be cautioned or sent off for abusive language or gestures.
"There should not be any surprises to any members of the teams," FIFA spokesman Alex Stone said.
Stone said there was no requirement for referees to know obscenities in languages other than English.
Wayne Rooney was booked during England's warm-up match against South African side Platinum Stars on Monday for swearing at the referee.