My husband and I moved here from Phoenix last November and have also been taking classes at the same school, albeit the location on C/ de Sardenya! The discovery I'm making as far as learning Spanish in Barcelona is that 1) although we were exposed to a lot of Spanish in Phoenix, it's a very different regional dialect(right word?), a lot of the words are different, idioms are completely different, and the accent is completely different - so the Spanish we are used to from Phoenix has not been as much a head start as we though it would be, and 2) it has taken a while to start to hear Catalan vs Spanish, as at first I was always trying to force my brain to translate what people were saying, when often they were speaking Catalan. So Barcelona is definitely a challenging place to learn Spanish. But we're getting there - we can do what we need to do in shops and restaurants, but just not to fluency yet.