The Berlitz approach to teaching foreign languages is nearly universally regarded as wrong-headed and out of date with what is known about how people learn and how the brain processes foreign languages.
In the beginning, Maximilian Berlitz, the recognized founder of the "Berlitz Method" was certainly ahead of his time. By happenstance, he hired a French language instructor for his school in Providence, RI without fully vetting his ability to speak English. As it turns out, Berlitz's new employee didn't speak a single word of English and proceeded to teach his lessons completely in French. Probably, the first immersion language course.
The students responded very positively. At the time, language lessons were very dry, filled with rote learning and declension exercises. This new form of teaching was more animated and certainly more fun because it included a lot of puzzle solving and guessing. The "communicative" approach to teaching was essentially born here.
And the "communicative" approach is today the prevailing theory in teaching foreign languages today, however, the Berlitz Method has failed to keep up with the times, and is basically about 100 years behind the rest of the teaching community.
Today, the Berlitz Method still stresses learning a foreign language the same way that you learn your native language. Which is impossible for 99% of the population. Science has shown us that we learn our first language, our native language, instinctively. To learn other languages, we use our intellect, and this is where the Berlitz Method fails.
The Berlitz Method has also been widely criticized for its "cookie-cutter" or "one size fits all" approach to students, teachers, and instruction methodology.