One of the main contributions that Chomsky had on language acquisition was to provide a very solid argument that language acquisition in adults is not different than language acquisition in children. So, yes :-). This is the generally accepted point of view at the moment. But this area is very, very difficult to test so there are still some people who disagree.
How is toddler learning by 'repeated exposure in a comprehensible way' when it lacks a vocabulary/understanding? My previous post was meant to point out fault in your reasoning.
Toddlers learn vocabulary and grammar from context. Here's one (somewhat limited) technique for teaching adult learners in a similar way: https://www.youtube.com/watch?v=j6De52Pzr8c It's called TPR (Total Physical Response) and relies a lot on tying physical actions to each concept. You can see that with the physical actions it is quite easy to create a context which is understandable for things like commands.
You can imagine that TPR can not teach all kinds of grammar or concepts (for example, how would you explain government). There are other techniques for creating a context that allows comprehension of these kinds of things. One of the keys is to teach yes/no questions early so that you can probe your student's understanding without them having to speak. It takes time for students to acquire the language well enough to produce.
This is quite an involved topic and many of the teaching techniques are quite new. I have used TPRS (Teaching Proficiency through Reading and Storytelling -- not connected with TPR) in the classroom quite effectively.
If you are interested in modern theories of language acquisition, I recommend reading "Principles and Practice in Second Language Acquisition" which is available for free download from Krashen's web site: http://www.sdkrashen.com/
Although it may have escaped your notice, I've tried to point out that this is not the only competing theory in language acquisition at the moment, but it is the one which has the most acceptance now (or at least 5 years ago when I was actively reading up on the subject). Learning language primarily from grammar rules has been discredited as an effective technique for at least 50 years now. Unfortunately educators have not kept up with current research. Having said that, my experience is that some knowledge of grammar can be useful as a supplement.
Which is of course false. When you're learning a language as an adult you can read and memorize the other language's grammar from a book. This significantly speeds up your learning.
Sorry, I was speaking sloppily on a technical topic. Language acquisition is the mechanism by which language that you can remember springs unbidden to your mind when you need it. Chomsky argued that the mechanism for language acquisition is the same for adults and children. It doesn't necessarily follow that the activities will be the same.
The person that posted was correct (as far as I understand it). Repeated exposure to comprehensible language (input) leads to acquisition (this is what Stephen Krashen argues, and which is the currently most popular theory as far as I know). The mechanism is the same for adults as well as toddlers (this is what Noam Chomsky argued, and which is generally accepted).
Memorising grammar is not necessary for language acquisition in children, nor in adults. The question is whether it can speed things up. Even if you agree with Krashen, it probably can because it provides a framework for reasoning about the meaning of something. It becomes an extra tool for creating comprehensible input rather than relying on context alone.
Many people believe that using grammar rules to generate output speeds the acquisition process. My understanding of the literature (now about 5 years out of date, unfortunately) indicates that this is not at all popular. In fact, it is said to be counter productive. My experience teaching English as a foreign language also supports the notion that constructing output from grammar rules should be avoided.
