How big a factor is language for international footballers?

I read about players like Christian Pulisic and Saki Kumagai playing in Germany and Toni Kroos playing in Spain, and wonder how big an issue language is for them in their first few years. It’s hard enough to communicate and play well with your teammates even when everyone speaks the same language, now how do they pull off playing at a world-class level in the toughest competitions when one may only speak broken German, Spanish or English? Not to mention, the off-the-field part like living, housing, and day to day life?

(Association) football is obviously continuous with team mates, opposition and coaches shouting (and a fair bit of that being absolute drivel) with a not-insignificant amount of background noise from the crowd the amount of verbal messages during the game that are effective is probably minimal.

Most of the on-field signals are body movements, hand signals and “shout name, then point” stuff. Train with a guy and it doesn’t take long to work out how they like to receive the ball, how they pass, how they create space. From then it’s primarily instinctive. There are nuances and variations but top level football is played with fairly similar methods across the globe.

Antonio Valencia captained Manchester United and was never interviewed in English despite being with the club for 12 years.

This is a good question.

As penultima_thule said, there’s not a lot of verbal communication during the game itself.
I’ve seen unmarked players call for a cross-field pass simply by raising their hand and forwards about to make a run point where they want the through ball.
The goalkeeper can shout “mine!” if he’s coming to catch a cross and wants his defenders out of the way.

My team is Spurs (Tottenham Hotspur in the English Premier League) and our centre-forward is Harry Kane (England Captain.) He scores a lot of goals because team-mates (especially Son Heung-min) know where Harry likes the killer pass to be played.

As for off-filed matters, clubs employ people to help players and families settle in. They translate, find suitable accomodation and schools and no doubt help with e.g. religion and cooking ingredients.

They probably also fairly quickly learn just enough vocabulary to be able to communicate in the limited context of their sport. It’s a lot easier to get to a useful level of proficiency in a language if you’re only ever talking about one subject.

Thanks, but there is still a lot of off the field stuff - like the manager giving pregame talks, setting the pregame strategy, signing a contract with the team, finding a place to live, etc. Do they have interpreters hanging around?

Sometimes the manager doesn’t speak the language of the country he is in!
So yes, big clubs have interpreters for team talks, if needed.

Players all have agents, who take care of the contract stuff for them.
(I reckon that unscrupulous agents regularly try to get their players to move, so the agent can get a cut of the transfer fee.)

As I said, clubs will help players find accomodation (and similar family stuff…

What language do the Swiss use in their locker room? How does management communicate with the players?

Mourinho started his career in Barcelona as Sir Bobby Robson’s interpreter, as Sir Bobby never learnt Spanish. Mourinho had been his interpreter already in Porto, where Mourinho would return as a manager to win League and Champions League. When Mourinho went on to become Real Madrid’s manager the Catalan press liked to tout him by calling him the interpreter.
Sir Bobby Robson also needed an interpreter to speak to the Dutch players and particularly to Romário during his stint at PSV. Romário did not listen, kept on partying and despite this PSV and Romário won the Eredivisie in both the 1990–91 and 1991–92 seasons.