I disagree. If Pep had actually learned German like he initially said he would, he may still be at Bayern. Its not just about giving instructions to players they understand, thats easy. Its about the tone, the ability to get the jokes, references etc. and not just with the players but the club staff, the media and the fans. If you dont speak the language, you ll always be the outsider - cant be an outsider and run the show.
Klopp is an extremely charming and likable fellow but its extremely doubtful this would have been fully appreciated by the media and fans in England if he hadnt been able to joke and “be himself” in the language they understand. Ive worked in multinational corporations for years and language is a common reason for people to flame out but also for performance issues in general.