Whenever neuroscientists tell us about the capacity and plasticity of the brain, they unavoidably mention language acquisition.
Dr. Lara Boyd, University of British Columbia, in her lecture-chat on TED, "After watchicng this your brain will not be the same" where she tells us about the plasticity and physical changes that occur in learning. Her chat sounded familiar. There was a ring to it. Yes, she was saying what Dr. Santiago Ramón y Cajal said over a century ago. He said, among many other things: "If he so proposes, every man can be the architect of his own brain" which is my translation of his words: "... todo hombre puede ser, si se lo propone, arquitecto de su propio cerebro..." (Los tónico de la voluntad, 1912.)
The gist (busilis) of it is that each one of us has a given potential, both scientists tell us, different from the potential of others. Some find it easier to learn a language, while others may find it more complicated or time consuming.
In effect, they tell us that, in the case of languages, there are no clear-cut methods because, in effect, again, each one of us is different and our neurons respond differently to stimuli.
Dr. Lara Boyd does not mention Santiago Ramón y Cajal, the man who said what she is saying now over a hundred years ago.