I just don't believe his claim: "C1 fluency in French in about 5 months" if he started from 0 unless he didn't do anything but learning the language in the target country. C1 is a damn high fluency: http://en.wikipedia.org/wiki/Common_European_Framework_of_Re... "Can understand a wide range of demanding, longer texts, and recognise implicit meaning. Can express him/herself fluently and spontaneously without much obvi…
C1 in 5 months without living in the country and speaking nothing but that language would put this person into "dangerously intelligent" territory. Super-human levels of language skills. With this "method", I have to wonder if he didn't just memorize phrases and words really, really well. Does he know the grammar and rules well enough to construct a compound thought on the fly and not sound overly foreign? Because you need to be able to do that for C1.