Nowadays many Universities and business schools offer all kind of courses in English, what makes easier for those students who do not speak Spanish at all, but at the same time some of hose students do not make any effort to learn it.
Sometimes it can be a little bit difficult for those students who work and study, but there are schools all over the city of Barcelona and, for sure, there are some options near your student housing or university flat. Furthermore, many schools are very flexible, offering courses with different schedules and length of time for all students.
Other advantage is that some of the Language Centers in Barcelona offer students' dorms, students' residency or have a partnership with companies this type of service of student housing in Barcelona.
We, from Barcelona Student Housing, have an agreement with some schools, so their students can have discounts or other benefits with the us.
I had studied Spanish at a Language Center in Brazil a few years before I go to Barcelona, but I had forgotten almost everything because I did not have the chance to practice it afterward. Like many other students who go to Barcelona, I chose a Master in English, so I did not have to speak the language to live there. But I decided to make an intensive course during my vacation, and that helped me a lot to improve it!!! I made a research to find the best option for me and I decided to study at “Escuela Mediterráneo”, because a friend of mine had studied there and recommended me. There are many other options of schools for students who want to learn the language, such as Enforex, Olé Languages, Barcelona Plus... so the student has to find the best option for him/her.
I strongly recommend, for all foreign students who live abroad at a country which mother language is different from yours, to learn the local language, because it is one the best ways to truly live the local culture. Furthermore, on a future job interview, they are certainly going to expect you to speak the language!
Do not waste your time and good luck!!! =)