Sportsmail understands manager Southgate advised his players to be aware of any profanities they use in the clash here in Rijeka at a team meeting earlier this week.
Because the stadium will be virtually empty due to UEFA sanctions dished out to Croatia, TV cameras and microphones are likely to pick up players voices during the game.
Gareth Southgate has warned England’s players over their language ahead of playing Croatia
Southgate and John Stones assess their surroundings on the eve of the Croatia match
No special measures are being put in place by broadcasters Sky for their pitchside microphones and they are not planning to put a delay on coverage.
But despite Southgate’s words of warning, he accepts it may be difficult to completely eradicate the expletives from his players in the heat of battle.
‘I think it’s for the television companies to decide where they put their microphones,’ said Southgate. ‘So it’s something we can’t prepare for, other than that we train in the same sort of environment every day of the week.’
Harry Kane and Harry Winks pictured disembarking the plane after it touched down in Rijeka
Kane poses with a worker (L) as Kyle Walker and James Maddison walk through Rijeka airport
Up to 500 England fans are due to be in Rijeka despite the supporter ban – but there are a number of vantage points around the stadium that would allow fans to watch the game. One local told Sportsmail that occupants of houses with a view of the pitch would let England fans into their property in return for payment.
On the pitch, having played with a back five during the World Cup, manager Southgate has experimented with a back-four in training this week.
That could see Kyle Walker selected at right back at the expense of Kieran Trippier. John Stones is set to start alongside Harry Maguire in central defence while Ben Chilwell is poised for his first international start on the left side of defence.
There are lots of vantage points to see the game from outside the ground, including this hill
Jordan Henderson and Eric Dier are expected to start in midfield. Ross Barkley is also pushing for a place in the team. Harry Kane is set to lead the line alongside Raheem Sterling and Marcus Rashford if Southgate decides to play with a back four.
Southgate, though, is set to rotate his players for Monday’s clash against Spain in Seville to ensure they do not return to their clubs tired.
Meanwhile, Tottenham academy chief John McDermott is set to be on the FA’s shortlist to replace outgoing technical director Dan Ashworth.
Southgate is set to select Walker at right back to come in at the expense of Kieran Trippier