Is it Possible to Learn Japanese While Sleeping? It Just Might Be!

One of the more controversial language learning techniques is learning while catching some Z’s. It sounds great, right? You simply turn on some Japanese audio before you go to bed, and when you wake up, you’re fluent. Is it possible to learn Japanese while sleeping?

It might be.

People on one side of this argument are saying, “Yes it works! Now buy my CD that teaches it to you!” While people on the other side are saying “That’s so dumb! You can’t learn while sleeping!” while they themselves don’t really understand how learning works in the human brain.

It’s an interesting question to say the least. I think you might actually be able to get some value out of the method, so lets talk a little bit about it so that you can decide for yourself if you want to do it or not.

What Do the Studies Say? Both Yes and No

They are actually a lot of studies done on the topic of sleep learning. Not only that, but there are companies that sell these “sleep learning CDs” for any topic that you can think of.

Why is it such a popular thing? I think it’s because the idea of learning something while sleeping is seductive. You get the benefits of hard work, but without having to put in the hard work.

People will typically take the path of least resistance in all things, so if they can just “pick up Japanese” while they are sleeping anyway, why not right?

Getting back to the scientific tests, there were a couple of really interesting things.

First of all, when they gave people words in a new language while sleeping, and then tested them on it after they woke up, they actually didn’t see any retention or recognition of the new language.

From just that result, you could claim that sleep learning doesn’t work.

But then another test did something different.

This time they taught two groups of people new words in a foreign language while they were awake. Then when they went to sleep, one group listened to a recording of the new words they had learned, while they other group did not.

Everyone was tested in the morning, and the people who had reviewed the language while sleeping, outperformed those who had not.

With this new information, we can add to the above conclusion that even if sleep learning doesn’t seem to work, sleep reviewing does.

To understand this, we need to take a look at the difference between new memories and existing ones.

How Does Learning Take Place?

The reason why you brain can’t really learn new words while sleeping is because, as an adult, your brain has developed what is known as the Reticular Activating System (RAS for short) whose job is to do three things to all incoming information:

  1. Delete
  2. Distort
  3. Generalize

Why does it do this? To keep you sane.

Simply put, there is way too much information coming into your five senses at all times, so your brain basically dampens the majority of it so that you can still function.

So what information actually makes it through to you? Important information.

The classic example is when you get a new car, and then you notice how many other cars of the same color or model there are on the road every day. You never noticed them before, but now you can’t stop seeing them!

That’s because the RAS was deleting them until you told your brain that “Blue Mustangs are Important to me now” and that’s when your brain started allowing you to actually notice just how many Blue Mustang cars are actually out there.

It’s the same with language.

Right now, you brain is ignoring all the Japanese words and phrases that it doesn’t know because it thinks that they are just gibberish and it doesn’t want to overwhelm you.

But when you take time to study words and phrases deliberately, then your brain marks them as important and you start noticing them.

(1) – I’m sure you’ve watched an anime in Japanese before and didn’t understand most of what they said the first time.

(2) – Then you studied a Japanese book or course and learned quite a few new words and phrases.

(3) – Then you re-watched that same anime, and this time you actually caught quite a bit more of what was being said.

Again, this is the RAS at work. This also explains why you can’t really learn new information while sleeping – because your brain is actively ignoring it.

But if you’ve already marked certain works as important, then you brain lets it through.

Isn’t is true that when you hear your name spoken while sleeping, you actually do hear it in your sleep, and often times wake up?

That’s because your name is the most important word that you know. You brain notices it.

What Role Does Reviewing Play in the Process?

When a new memory is formed, your brain lays down a neural connection for it.

Then when you review that same information, you brain strengthens that same existing connection, or makes a new one to the same place, if the same information was presented in a different format.

After you do this for a while, those networks become very strong and your brain is able to use them with incredible speed and efficiency.

That’s why the Japanese words you see all the time are easy, but the longer and more abstract ones still give you trouble: because those connections are weaker.

This is why you need to not only learn Japanese, but also review what you’ve already learned, as you go along.

It’s also the theory behind Spaced Repetition Systems (SRS for short). You see the same information up for review at the beginning a lot, because that’s when the neural connections are weakest. Then as you continue to review them, they get pushed further out in to the future, since you don’t need to go over them as much when the connections are strong.

Knowing these two things, how you learn new Japanese and how you strengthen existing memories, will set the stage for how you can actually learn information while sleeping.

How To (Actually) Learn Japanese While Sleeping:

It’s actually kind of a misnomer, since you won’t really be learning anything, instead you will be solidifying what you learned while you were awake.

You can give yourself a head start with all of this when you first encode the new information, if you do so in such a way that it burns it into your brain.

But even then, you’ll still want to “re-walk those paths” in order to stamp the grass down and make it a permanent road for your brain to travel each and every day.

What this means is that, the only Japanese audio you should be listening to at night, is one with words and phrases that you’ve already learned while awake.

You could re-listen to the audio of things like Pimsleur and Michel Thomas, as they are both audio courses. But the main problem with these two is that they are formatted to teach you a few Japanese words and phrases really well.

That means that you might only hear Japanese for 5-10 minutes out of a 30-minute lesson, and there’s going to be a lot of English explanations going on.

Instead, you might just want to use Japanese conversations from books or courses that have a “Japanese only” audio.

There are three that I’ve used myself like this:

All three of these will teach you Japanese in a deliberate way, but the accompanying audio is just Japanese so you get the maximum “air time” with the language on the audio.

Once you’ve got something similar to that, you will want to use this process:

  1. Study the material while awake, including listing to the audio portion.
  2. Listen to the audio throughout your sleep.

You could simply put the audio onto your phone, plug it into the wall, and then play it on repeat throughout the night.

This way your brain can hear the Japanese words that it knows are important, and strengthen those existing neural networks even further.

When Should You Not Use This Technique?

I give you this technique, but I don’t recommend it for everyone. We already know it’s not necessary to do it in order to learn a language, as the majority of people who have become fluent in a second language never went to this extreme.

And of course, this might be totally impractical for you if you’re married and don’t want to bother your spouse all night.

It’s even possible that you might have a hard time sleeping when there’s noise going on, and this method might just keep you awake and actually prevent you from getting a good night sleep.

In all of these situations, I would advise against listening to Japanese while you sleep. For one thing, you absolutely NEED sleep! Not just for a healthy body, but it’s also needed for long term memories to be formed.

And you don’t want to get murdered in your sleep by your S.O. if they can’t sleep either!!!

What’s your experience with listening to Japanese while sleeping?

Is this something that you’ve found helpful in the long run? Or do you think it’s more of a pipe dream kind of thing?

Let me know down in the comments!


  • stella

    Hi Nick,
    You got me with that topic,” Learn Japanese while sleeping” . I had a good laugh at first but after reading your post which is very educative, I agree with you. It is better to learn a new language while you are awake, It might help to listen to the audio while sleeping but you will actually learn by paying attention which means being very much awake.

    • Nick Hoyt

      Yeah, there’s really no substitute for a consistent study schedule where you’re relaxed and focused, and using a comprehensive input method of learning. It is perhaps the most efficient way to learn a language. 

      But most people consider it work. And it can definitely be boring when you’ve been doing it for a while and you’re not seeing those huge gains like you did when you first started, and you’re still not quite good enough to read the majority of interesting books and manga that are out there.

      It’s times like that when people are attracted to finding shortcuts to learning Japanese. Though like I mentioned, the studies show it can be helpful when you listen to words you’ve already learned before.

      I guess the question really comes down to “how quickly do you want to learn the language?” If you want to be fluent in months, then you’d definitely want to do everything you possible could to get there, but if you’re okay with spending several years at the task, then there’s really no need to listen to Japanese while you sleep.

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