source wikipedia
Switching to FC Barcelona in 1996, where he learnt Catalan for the new challenge. Mourinho and his family moved to Barcelona and he gradually became a prominent figure of Barcelona's staff by translating at press conferences, planning practice sessions, and helping players through tactical advice and analyses of the opposition. Robson and Mourinho's styles complemented each other: the Englishman favoured an attacking style, while Mourinho covered defensive options, and the Portuguese's love of planning and training combined with Robson's direct man-management. The partnership was fruitful and Barcelona finished the season with the European Cup Winners' Cup. Robson moved club the following season but this time Mourinho did not follow as Barcelona were keen to retain him as assistant manager.The two remained good friends and Mourinho later reflected on the effect Robson had had upon him:
One of the most important things I learnt from Bobby Robson is that when you win, you shouldn't assume you are the team, and when you lose, you shouldn't think you are rubbish.
He began working with Robson's successor, Louis van Gaal, and he learnt much from the Dutchman's conscientious style. Both assistant and head coach combined their studious approach to the game and Barcelona won La Liga twice in van Gaal's first two years as coach.
Van Gaal saw that his number two had the promise to be more than a
skilled assistant. He let Mourinho develop his own independent coaching
style and entrusted him with the coaching duties of FC Barcelona B.Van Gaal also let Mourinho take charge of the first team (acting as
Mourinho's assistant himself) for certain trophies, like the Copa Catalunya, which Mourinho won in 2000.