Gaizka Mendieta should know a thing or two about the Spanish Valencia Football Club and their fans, considering he was a key player on the team for over eight years. So when he warned new Valencia CF manager, Gary Neville, earlier this week to learn Spanish, the ex-Manchester United defender probably took notice.

Mendieta made the warning on “The Little Big Interview with Graham Hunter” podcast, reports The Daily Mail.

“The language barrier is a big thing because Valencia fans like to hear, like to be treated, like to be adored and taken into consideration,” Mendieta said. “I’ve seen big managers being frustrated because they can’t speak the language and basically communicate with the words they want to get in your mind.”

Neville takes over the Spanish squad after Portuguese Nuno Espirito Santo, a former goalkeeper, ended his term as the team’s manager after just 13 matches played since taking over in July of 2014. Mendieta’s warning comes on the heels of Santo’s abrupt departure after fans allegedly turned on him because of the team’s ninth place La Liga standings.

While engaging in a Spanish curriculum to speak the native language might seem like a trivial thing for such an international sport, Mendieta sees it more about a matter of respect in the fan’s eyes as they will hold great influence over the climate of his tenure.

Regardless of how well Neville’s managerial tenure works out in Spain, he can surely benefit from brushing up on his Español. The language is the second most-spoken language globally, with around 387 million native speakers worldwide.

“It’s a delicate and fine line between the fans, but you need them because we’ve seen what happened with old boss, Nuno. The fans change their mind and that’s it you don’t get them back,” Mendieta said. “Results in football are the most important thing. But it’s not just the football, it’s also the relationship with the fans and that’s going to be important for Gary.”