No, I’m not buying it. Can you learn a language mainly through comprehensible input? Absolutely, positively yes. Is it quick and efficient? No. Children take five years of 24/7 immersion (realistically, probably about 10000 hours of actual “language work”) to acquire their “native language”, and at that point they speak it like a five-year-old. That’s actually a very good place to be, but sadly, not one that most adults are interested in. Personally, I am interested in that outcome as a first step in my language studies, but it’s not going to take me five years of study, much less 24/7 immersion, to get there. And I am patient, just not willing to waste time. I love comprehensible input as well, but why spend 10000 hours of listening when you can “cheat” by looking at a grammar book and actually studying useful vocabulary. Would someone please explain the appeal of the so-called "learn like a baby" method?

There are those who don't like the word acquisition, saying that it's an artificial distinction. Even so, this is what it means:

Acquisition is a relatively slow process but still the natural way, and perhaps also the best way to get a good command over the target language. It does not call for any vocabulary memorization, learning grammar rules or translation. At least not initially. What it does need is immersion in all possible forms, which means regular exposure to the spoken and written language in any manner. The best immersion is to be in a country where the language is actively spoken, but other forms work too, as long as one is regular. And then, when one feels they instinctively have enough words and basic structures, one starts speaking. To begin with they keep getting stuck and speak with very bad grammar, but if they persist on a regular basis, that improves substantially soon enough. Languages acquired in this way aren't easily forgotten because it gets truly internalized.

I think that everyone should choose (or build) the optimal method of language learning individually. For someone, some methods are better suited, for others - other methods. (are more effective or just more enjoyable, etc.).

For example, polyglots use completely different approaches.

I recommend to watch a video about this:

<a href="https://www.youtube.com/watch?v=ROh_-RG3OVg" rel="noopener noreferrer" target="_blank" style="background-color: rgb(255, 255, 255); color: rgb(102, 0, 153);">Lýdia Machová - Ten things polyglots do differently</a>

Briefly, there is its content (timing added) and essence:

1. Polyglots don't have a special talent! 15:07

2. Every of polyglots has their own method 16:34

3. Polyglots learn languages mostly by themselves 17:08

4. Polyglots create their own language material 18:31

5. Polyglots learn one language at a time 19:12

6. Polyglots spend much more time listening and speaking 20:32

7. Polyglots are not afraid to make mistakes 23:12

8. Polyglots have mastered the art of simplification 24:50

9. Polyglots learn in small chunks 26:20

10. Polyglots enjoy, MAKE language learning their addiction 27:10

Summary

Initial Insights

- Polyglots manage the quality of time, rather than quantity

- Polyglots have the personalised system, though have common traits

e.g. of systems

- Speak from day 1(Bennie Lewis) - a method similar to Acquisition

- Material (Steve Kaufman) 

- High-frequency words (Lucas Rafael Bighetti Pereira)

- Flashcard system w/o translation 

- Robin McFernon (dissection) 

- David James (Re-write vocab list) 

- Phrases then fun, material, consistency, priorities (Lydia) 

Phil - you're knocking these methods for their "slowness" and throwing out a 10,000 hour number. But Jeff Brown's video is based on learning Arabic in 800 hours (less than the State Department rating of 2200 hours, but he's speaking only. I didn't watch closely enough to see if he's claiming that his method succeeds more quickly than those estimates). The Lydia Machova video doesn't present a single method, but invokes principles which seem to be based on a similar level of commitment (<2 hrs per day for awhile)

Appeal? We know that "learning likes a baby" has a near 100% success rate. Traditional classroom learning doesn't.

Lydia Machova. Luca Lampariello. Tim Doner. No doubt they are all inspiring figures but I believe that it's unrealistic to take the reference of celebrities. One must consider that they are celebrities due to a combination of three factors: some special talent or aptitude in the given field, unfailing grit and determination and the chance factor also called good luck in common parlance. What works for them needn't work for us and vice versa. As Lydia says, language acquisition strategies are personalised and as individual as individuals are themselves.