Is everyone WRONG about Stephen Krashen's "comprehensible input" theory?

Language YouTube is obsessed with one man. Video after video praises Stephen krayshen, and his theory of comprehensible input. It’s the best way to learn a language.

It’s the ONLY way to learn a language. Throw away your textbooks, forget about grammar, it’s all about comprehensible input. But is everybody getting his theory wrong?

SORT OF. I’ll explain why it’s a little more complicated than people make it out to be, how solid it actually is, and what we can still learn from it. I’m Dr Taylor Jones, and this is Language Jones.

I’ve seen people say that Chomsky is wrong about language, and two seconds later swear their intellectual allegiance to Krashen, without realizing that not only does he know and get along with Noam Chomsky, not only does he pronounce his name correctly, but his theories are within a chomskyan framework. What you’re likely to see on YouTube is a claim that all you need to learn a language is a sufficiently large quantity of engaging, comprehensible input. Comprehensible means that you can figure it out.

Ideally, that there’s only one new word in a sentence, or one new structure that you can get from context. And Input is just your target language. By this interpretation, the only thing you need to learn a language is a LOT of the language, starting simple and getting more complex, preferably with something like pictures or video, and ideally with native audio.

But that’s not exactly what Krashen meant, and in his original theory, he actually specifically addresses the fact that THAT SOMETIMES DOESN’T WORK. So let’s get into what his theory actually is, and then decide how justified it is, and whether we can make it work for us. His writing covers not just the Comprehensible Input Hypothesis, but also four other interrelated hypotheses.

If one proves wrong, it might destabilize the whole academic endeavor. And notice, they’re hypotheses! These need to be operationalized and tested.

He’s working within a chomskyan, generative framework, and those assumptions are actually the first hypothesis. But I’m getting ahead of myself. What are the five components?

They are: 1. Learning vs acquiring 2. (Linguistic) monitor 3.

Natural order 4. Comrpehensible input 5. Affective filter Stick around to the end and I’ll add two more components that nobody discusses about Krashen’s theory, even Krashen himself, but that we should be aware of.

So the five components. First is the hypothesis, or really assumption, that there is a difference between learning and acquiring a language. Learning is explicit, taught, and consciously accessible declarative knowledge.

Acquisition, on the other hand, is what children do. They are not explicitly taught, say, how to make sure anaphors like “himself” occur in the correct grammatical frameworks with the correct dependencies, yet somehow they start to produce language we would consider grammatical, despite in many instances having never heard the exact sentences or sentence structures they use from adults. That is, there appears to be a developmental stage — a mental module — where children simply start using finite grammatical structures to produce infinite possible language combinations, in orders we would consider grammatical.

Where Krashen argues with Chomsky is the Critical Period Hypothesis. There’s a fair amount of evidence that if people start to learn a language too late, they will never attain native-like fluency in grammar and phonology. But It’s really hard and more than a little immoral to test this, and there’s a lot of confounds, and basically Krashen just disagrees.

He has stated over and over that he doesn’t think we get worse at ACQUIRING language as we age, even past 25, when the prefrontal cortex is done cooking and we start losing neuroplasticity (on average). I’d like to acquire 100,000 subscribers, so now’s a great time to like and subscribe. Brutal Segue.

His second hypothesis is that of the linguistic monitor. This is similar to Bill Labov’s “sociolinguistic monitor” (shoutout to Bill, one of my advisors in grad school). The idea of the sociolinguistic monitor, put simply, is that we speak in a way we think others will perceive as more “correct” when we are not stressed or agitated, and have a lot of cognitive resources to put toward that.

He phrases it differently because the neuroscience wasn’t as developed when he came up with this. This is why sociolinguists will do reading tasks and polite conversation, and then start getting into questions like “tell me about a time you almost died. ” Our job is, in part, to get people so worked up that their “natural” vernacular comes out because they’re no longer monitoring how they speak.

Krashen’s linguistic monitor is similar. He argues that we have a store of our target language that we have acquired, somehow, and that what we have LEARNED merely functions as a monitor — basically, has veto power to correct what we intuitively generate. We’ll come back to what happens when we’re cognitively taxed shortly.

So I might KNOW, in a declarative sense, that in French you use the future tense in both parts of a future conditional — I will speak French when I will be in France, instead of “I will speak French when I am in France. ” But I might only be able to generate such sentences when I am monitoring my speech, and I’m likely to produce a grammatical error UNTIL I’ve seen sufficient examples of sentences that use that structure correctly in French so that it just “feels” better. His third hypothesis is about natural order of language learning.

There are some really fascinating patterns when children first learn language, and they’re cross-linguistically basically the same. Things like saying “I no like it” first, and only later developing “don’t” in imperatives first, then in sentences like “I don’t like that. ” And only much alter being able to consistently get negation correct in sentences with multiple clauses, or conditionals or so on.

This is a topic that deserves its own video, and I’ll be making one soon. For a long time, it has been known in the field of second language acquisition that, in general, non-native learners’ interlanguage — their use of their target language while learning it — follows the same, evidently hard-wired order of acquisition. This goes for everything from negation to matching the appropriate gender on posessives, to how questions are formed.

Krashen hypothesizes that this order of acquisition that non-native learners tend to follow, and which mirrors that of children leanring their first language, is natural, and hard wired. So why bother starting with declarative explanations of grammatical patterns that we know from experimental evidence learners will likely NOT learn upfront? Especially if these patterns are basically impossible to acquire in that order?

That is, that’s the hypothesis. It’s not settled fact, but the experimental evidence is suggestive. His fourth, FOURTH hypothesis is what people refer to as comprehensible input.

That is: if you accept the hypotheses — and these are not proven — IF you accept that we do not learn, we acquire, and that there is no strong correlation between age and ability to acquire that is biologically innate, and IF you accept that what we produce is what we have acquired and what we have learned is merely a cognitively taxing, conscious last check on the acquired language that wells up from our depths, and IF you accept that there is a natural order to acquisition, such that it doesn’t matter what order you are exposed to the language in, THEN he HYPOTHESIZES that the best approach is to get as large a volume as possible of “comprehensible input. ” Input just means your target language. Comprehensible, in this case, means that you learn at most one new thing at time.

He sometimes calls it “i+1”: This can be new vocabulary in a sentence frame you don’t know, or a new grammatical construction that you can figure out correctly because you know context and it’s using all words you already know. It’s not always clear whether he endorses translation and lookup and so on, or if he’s implicitly endorsing an immersion methodology. The key is also once you have your “i +1” you need sufficient input, sufficient repetitions of that, to acquire it.

So it’s not just chasing the dopamine hit of a new word all the time! . Lastly, there’s ANOTHER hypothesis.

I promised I’d get back to cognitive load. He calls it the “affective filter. ” The idea is that if you are experiencing negative affect, that is negative emotions, all of this is harder.

This is REQUIRED in his system, because there is a lot of evidence that the first four, on their own, DON’T ALWAYS WORK. So his theory is that people get stressed, or upset, or in their heads or in their feels about language learning, and it shuts down their ability to acquire. This is the principle Michel Thomas built his reputation on.

It’s probably correct in some sense, in that we know that general learning is impeded by cognitive strain. But notice, this is necessary because even if we assume that each of the first four hypotheses are correct, and do everything that assumption would entail, people fail to become proficient in their target languages. So the AFFECT FILTER is a way of explaining away what happens when a large volume of comprehensible input fails to produce a language learner who is competent in their target language.

There are a lot of videos on YouTube that tell you not to study grammar, and that “comprehensible input” is all you need, but they’re leaving out a lot of the story! A ton of content, even if it is engaging, and even if it is at a level where you can figure it out from context, does not always produce a learner who can understand and meaningfully engage with a wide range of uses of their target language, or one who can produce comprehensible and “correct” language. There is also an entire world of Second Language Acquisition research out there, and a lot of research points toward empirical support for the benefits of general learning best practices, like training active recall, “desirable difficulty” and so on.

There’s two more points I think are really important, but first, leave me a comment and let me know if you want a breakdown of Chomksy’s Universal grammar, and what the Youtube polyglot community gets wrong about it. Assumign I can fit ALL of that into one video. Ok so there’s another thing I haven’t seen anyone mention, but I think it’s important.

Krashen recommends a massive amount of reading for fun. Specifically reading, although he does like comic books and graphic novels. But this doesn’t necessarily work for everything.

I’m incredibly excited to have found this children’s encyclopedia in Hebrew, WITH VOWELS. But the majority of the reading material I could find, even graphic novels, will NOT have vowels. This makes leisure reading for continued exposure in the hopes of acquiring Hebrew a fruitless task.

Plus, how many people read Hebrew, specifically, in large volumes without knowing what they’re saying? Lastly, I have a bit of a tangent that I also think is really important, drawing on Krashen’s statements in an interview with hyperpolyglot Richard Simcott. Now, I’m not a medical professional, and anything I say here will be speculation and not a diagnosis (great start, I know).

But —for REASONS — I have been doing a deep dive on ADHD and other neurodivergencies so to speak, and a story he tells about his first experience with coffee caught my attention. For those of you who watch my live streams, you know I think about how ADHD, autism, and other factors might play into language learning success or failure. Anyway, he discusses being aimless in life, and going from one thing to another, not achieving anything, and says that while in Ethiopia, he was given his first coffee, and it was a double dose of Ethiopian coffee.

The hardcore stuff. And he describes it as scales falling from his eyes, and says that he remembered wondering “is this how everyone feels? ” And from that point on he was addicted to coffee and suddenly able to execute tasks he was interested in, and pursue his life’s passions.

I, again, am not an expert, but this sounds a LOT like what Andrew Huberman describes in discussing undiagnosed ADHDers self medicating with stimulants. And if we posit that Dr Krashen might be close to that side of town, as I sometimes descibe myself, or even across the tracks, then a lot falls into place about the effectiveness of his method, especially for him. Rather than following the grammar-translation approach, which is fairly rigid, structured, and requires a ton of motivation and executive function, self directed fun engagement with the language without rigid structure, with the goal of experience as much mental stimulation in the language as possible at a level that is delightfully challenging but not overwhelming, sound IDEAL for the add language learner.

So regardless whether Dr Krashen has or had undiagnosed ADHD that he stumbled upon self-medication for in the form of coffee, he came up with a language learning approach that is potentially much more effective for those among us who do have ADHD. And it’s almost diametrically opposite to the approach taken by a lot of academic linguists. Academic linguistics seems to select for Autism at a MUCH higher rate than the general population, but that’s another video for another day.

The point being, hyperfocus on structural analysis might play to one kind of neurodivergence, and massive amounts of undirected input, allowing for flipping among and between sources and getting constant little dopamine hits might play to another. So what’s the verdict on comprehensible input? Well, honestly, the academic jury is still out, though there is a small and very vocal Youtuber contingent.

Part of that is because acquisition versus learning, within a Chomskyan framework, is still not fully settled science, and the linguistic monitor model is a conjecture based on that. But it’s clear that exposure to a large volume of your target language, at a level that you can engage meaningfully with is better than not having that. But it may still be the case that analyzing that language, or doing more cognitively taxing work — things like active recall, and self-assessment, for instance by comparing your recorded speech to a native speaker — are probably beneficial to MOST people, and will speed the process further.

However, if we take neurodivergence into account, Krashens’ approach seems almost tailor made to play to the strengths and minimize the weaknesses of an ADHD learner, so if that’s you, maybe prioritize input over everything else! Leave me a comment and let me know what’s worked for you! You can support the channel by becoming a patron at patron.

com/languagejones. Shout out to all my patrons. If you liked this video, I’m sure you’re going to enjoy THIS one as well.

Until next time, happy learning!