Here is a great comment from Ben Slavic’s Blog
Don’t remember where I read this, but it was by a biggie in the SLA world (VanPatten I think) who believed that learning styles do not apply to language acquisition. There is only one way to acquire language and that is by comprehending messages. Language acquisition is so specialized and mainly unconcious that learning styles and their accompanying types of activities are not effective. I’ve dug up a few other quotes that I’ve used during workshops that really help explain the importance of input. I’ll paste them underneath and Ben you can use as you wish if you haven’t come across these already.
(From Input to Output, Bill VanPatten, p.25)The concept of input is perhaps the single most important concept of second language acquisition. It is trivial to point out that no individual can learn a second language without input of some sort. In fact, no model of second language acquisition does not avail itself of input in trying to explain how learners create second language grammars.
(Gass, 1997, p.1)
Although SLA as a scientific discipline is only four decades old, one of the most fundamental discoveries that revolutionized the way people thought about how languages are learned involved the concept of input. Although it might be a bit grandiose to imply that the discovery of the role of input is on par with the discovery of the earth’s rotation or the existence of the subconscious, the point here is that in the small work of SLA research, the discovery of the role of input completely altered the way in which scholars conceptualized how languages are acquired. Today, all theories in SLA research accord input an important if not critical role in how learners create linguistic systems.
(VanPatten, 2003, p.28)
Language acquisition happens in only one way and all learners must undergo it. Learners must have exposure to communicative input and they must process it; the brain must organize data. Learners must acquire output procedures, and they need to interact with other speakers.
(VanPatten, 2003, p.96)
Every successful learner of a second language has had substantial exposure to input as part of the process of language learning.
What kind of input is optimal for acquisition? The best input is comprehensible, which sometimes means that it needs to be slower and more carefully articulated, using common vocabulary, less slang, and shorter sentences. Optimal input is interesting and/or relevant and allows the acquirer to focus on the meaning of the message and not on the form of the message. Optimal input is not grammatically sequenced, and a grammatical syllabus should not be used in the language classroom, in part because all students will not be at exactly the same level and because each structure is often only introduced once before moving on to something else. Finally, optimal input must focus on quantity, although most language teachers have to date seriously underestimated how much comprehensible input is actually needed for an acquirer to progress.
A Summary of Stephen Krashen’s “Principles and Practice in Second Language Acquisition” By Reid Wilson