Spain is a country with diferent cultural regions. It has Catalunya, a zone where they speak Catalan (yeah you know, all the independentist movement and everything was there.) Valencia, a really party zone in Spain (Gandia). Madrid the capital of spain. Andalucia were flamenco was born. Basc country, they speak basc too there. (It is at the north of Spain and it is a must visiting it.) Galicia, they speak gallego. (It is at the west of spain next to Portugal.) etc.
Well, there are a lot of zones in Spain, if you are going in erasmus there you can discover each below. (ONLY CATALUNYA AND VALENCIA IS AVAILABLE AND NOT COMPLETED)