Miriam makes some good points — it depends on the relationship of your native language to your target language, and the number of hours you can dedicate to practice. You absolutely don’t have to move anywhere — that’s what the internet is for. If you’re PT-BR learning Spanish from scratch, then one month is actually feasible. (By fluent, I just mean able to hold ordinary simple conversations, get your point across, and understand the person you’re talking to. Don’t expect to wow anyone with your rhetorical skills or brilliant prose.) If you were learning English from scratch, three months would be well within reach (but you’ve got quite a good head start on that, don’t you?). I had one Brazilian student — out of hundreds — who went from zero to holding business conversations in two months. He put in full-time hours. Warning: Intensive study leads to quick gains, but you’ll need to actually use the language afterwards or you’ll forget quickly. If you have a real need to learn the language, then intensive study can be the perfect solution, but if it’s just a stunt to impress friends on social media, I cannot recommend it at all. Personally, I prefer slow and steady progress, but intensive study can be the perfect solution for some people in certain circumstances.