There`s absolutely no excuse not to learn the language, at least to conversational level.Everybody gets booed from time to time, it's part of the game if you play for Real Madrid. Greatest club in the world, highest expectations. At the start of the season he didn't score for 6 games, and was generally bad. The season before he was quite average (in Real Madrid terms) - partly because of injuries. I think if I were to look up the amount of injuries he's had over the last three years I'd be quite amazed.
He also isn't really endearing himself to fans with his refusal to learn Spanish. He's been there for 5 years or something and he still doesn't speak the language on a somewhat decent level. It's not a hard language; he appears to be too lazy to learn it or make an effort. Beckham you saw he really struggled but at least he tried and tbf he improved. They appreciated that.
I`d take it as an insult too, if a player had been here for that length of time and hadn`t bothered to learn English.
I remember Tevez never learnt English in all his time here.