Hola, soy uno de esos lunáticos catalanes independentistas...
Que no, que no, que es broma.
No tendrás problemas para comunicarte en castellano aquí, además estamos muy acostumbrados al turismo, así que no te preocupes, que la gente hace el esfuerzo de entenderte y hacerse entender.
While staying here in Barcelona, just relax, enjoy the weather, talk as much as you can with everyone,(forget about writings) don't be shy, people won't laugh at you if your spanish is broken, we are used to receive visitors/tourists.
If you wish I can recommend you some really nice places to get fun and socialize with other poeple.