A couple of years ago, a Spanish girl, about 20 years old, answered one of my ads for English classes. She had a very low level of English, but had decided that she now wanted to learn it once and for all. During our initial conversation, she asked me straight out: "¿Cuánto tiempo necesito para aprender inglés?" - "How long will it take me to learn English?"
I admit that I was speechless for a second (and this doesn't happen very often!). I replied: "Well, if you have a photographic memory, an excellent and refined sense of hearing, a profound knowledge of the grammar in your own language, an IQ of at least 150, and if you are willing to work on it for no less than 8 hours a day, you'll be speaking fluently in less than a month!"
That "less than a month" part was probably what put the delighted smile on her face, but then, looking more serious, she asked: "And if I don't have all those qualities?" I answered: "Then you're probably looking at a few years, that is, unless you decide to spend this summer in England or America, in which case you'll progress more quickly."
Obviously, mastering a foreign language has much to do with our natural talents. Years ago, I read an article about the German Grand Master of Chess, Robert Hübner. It seems that he had to go to Hungary for a tournament, but unfortunately, didn't speak the language. No problem! He bought himself a good book, boarded the train, and when he arrived in Budapest after an eight-hour journey, he could speak Hungarian more than well enough to get by. Of course, Herr Hübner almost no doubt does have a photographic memory, an extremely high IQ, and so on.
I myself have nowhere near the mental brilliance of a Robert Hübner (if my accomplishments, years ago, on my college chess team are any measure of this), though I am certainly not without talent as far as language learning is concerned.
Sorry I don't speak Spanish, so if I messed up that part I apologize!