The Truth: Can You Learn a Language in Your Sleep?

It’s no secret that learning a language takes effort and time. In fact, according to the U.S. Department of State’s Foreign Service Institute, you need approximately 600-750 hours to learn a Category I language, which are languages most closely related to English (e.g. Spanish, Italian, French, and Portuguese). On the other hand, you need approximately 2200 hours to learn a Category IV language, which is “exceptionally difficult for native English speakers” (Arabic, Japanese, and Mandarin). It might seem like there is never enough time to learn and process everything you’re supposed to learn. If only there were some interesting hack that you could use to learn a language… such as learning a language in your sleep. Is that even possible?

What is sleep learning? And why is it controversial?

In the 1960s TV sitcom My Three Sons, in an episode called “A Lesson in Any Language,” the eldest son, Mike, is trying to learn Spanish by placing a tape under his pillow to listen to in his sleep. When his father, Steve, sleeps in his room while Mike is on a trip, he becomes fluent overnight! That is essentially the idea behind sleep learning: conveying information to a sleeping person — usually via a tape recorder or, in our modern world, movies or YouTube videos — with the  goal of retaining this new information. 

Given how many hours of our lives we spend sleeping (26 years of it, to be exact!), some people find the idea of sleep learning appealing, especially if that means a shortcut in language learning acquisition or other knowledge. However, sleep learning is actually a controversial topic. Studies have shown that even though sleep helps with retaining information (emphasis on “helps” here), and according to researchers like Simon Ruch and Katharina Henke in Cognitive Sciences (1955), learning in one’s sleep would be a dream come true. Still, the sleep learning phenomenon is criticized “in terms of weaknesses in experimental design, statistics and methodology employed, and criteria of sleep”. Let’s not give up yet. Let’s dig into some other experiments.

Is learning a language in your sleep possible?

In a groundbreaking study in 1924 by researchers J. G. Jenkins & K. M. Dallenbach, participants learned a series of syllables in the morning or evening before bed. After being tested 1, 2, 4, and 8 hours later, the results showed a much slower rate of forgetting when the participants learned the series at night before going off to bed. In other words, sleeping can play a role in retaining information longer.

Fast-forward to 2015, in the Swiss experiment “Boosting Vocabulary Learning by Verbal Cueing During Sleep,” scientists tested whether verbal cueing during sleep could improve vocabulary learning. They cued German native-speaking participants learned words in Dutch during NonREM sleep or active or passive waking. The results showed that re-exposure to the Dutch words during sleep improved later memory for the German translation of cued words compared to uncued words. This only worked during NonREM sleep:

“High-density electroencephalographic recordings revealed that successful verbal cueing during NonREM sleep is associated with a pronounced frontal negativity in event-related potentials, a higher frequency of frontal slow waves as well as a cueing-related increase in right frontal and left parietal oscillatory theta power. Our results indicate that verbal cues presented during NonREM sleep reactivate associated memories, and facilitate later recall of foreign vocabulary without impairing ongoing consolidation processes. Likewise, our oscillatory analysis suggests that both sleep-specific slow waves as well as theta oscillations (typically associated with successful memory encoding during wakefulness) might be involved in strengthening memories by cueing during sleep.”

Therefore, according to this study, verbal cueing while sleeping can potentially help you strengthen your vocabulary memory. Notice how the words must be learned first. A good example of this would be studying French vocabulary before going to sleep and then listening to a recording of yourself (or someone else) repeating these words. It’s important to keep in mind that this reinforcement only happens during NonREM sleep.

How do you learn a language?

It might surprise you to know that wild chimpanzees use over 66 hand signals and movements to communicate. Many primates communicate through gestures, dogs through actions like tail-wagging, and dolphins by clicking and whistling. This is without even mentioning the role of pheromones in species communication! However, we are the only species that speaks a language or can sign in a language (e.g., American Sign Language, Australian Sign Language, etc.). Gorillas, for example, can learn some basics of language signing, but there is no syntax or grammar, which is a foundational component of language.

This complexity of language, with its structural components and what is fundamentally a deep expression of thoughts and ideas, is what sets the human species apart. It is true that scientists are unsure as to when language evolved, but it is estimated to be as late as 50,000 years ago and as early as 2 million years ago. Even though we also do not know why language evolved, a 2015 study concluded that it might’ve been to help our ancestors make tools. One thing is certain: language has helped us not just pass on oral and written history, cultural beliefs, and traits; it has also helped us survive and thrive as a species. 

There are three main areas of the brain associated with language learning:

1. Broca, in the left hemisphere, is linked to speech and articulation in both spoken and written language.

2. Wernicke is in the posterior superior temporal lobe and is connected to Broca’s area. It deals with comprehension and language processing.

3. The angular gyrus helps us make the association between language-related information received visually, through hearing, or touch.

We start learning and mimicking the language and sounds from the time we’re babies. Research shows that language learning and sound distinction potentially start in the womb.

Does getting a good night’s sleep help with learning a language?

Getting a good night’s sleep can definitely help you learn a language. According to researchers Susanne Diekelmann, Ines Wilhelm, and Jan Borns’ research paper, “The Whats and Whens of Sleep-Dependent Memory Consolidation” sleep helps with memory consolidation, but it is dependent on certain psychological conditions, such as types of learning materials used.

Another study with high school students examined the participants’ ability to recall vocabulary and proved that memory is enhanced when they go to sleep within a few hours, irrespective of the time of day. Sleep deprivation, on the other hand, has a detrimental effect on memory, according to the researchers.  Like with other skills, feeling healthy, alert, and rested goes a long way when learning a new language.

More effective ways to learn a language

After spending 15 years in language education, I can tell you that there is no shortcut to learning a language. It takes a mixture of patience, work,  perseverance, and a great attitude. So maybe you can’t learn a language in your sleep, but here are 5 effective things within your control that you can do to learn a language faster:

1. Get a language parent. We’ve all had a language parent at one point or another in our lives, whether that is your biological parent or a language teacher. If you’re learning a language as an adult, I’m referring to a language teacher who will assess your progress, hold you accountable, and basically show you the ropes in this new journey. You can read about this tip and other good ones by instantly downloading my free guide, “10 Tips to Become Fluent in a New Language Faster”.

2. Sign up for a language class. This is a great way to make new friends, build rapport with others who share your same interests (travel, anyone?) and learn something as a group. I can’t emphasize enough what a tremendous bonding experience language learning can really be. Also, the level of accountability you will get when you have a class to attend every week at 10:00 AM is very different from just playing languages on an app. It will ingrain a habit and a ritual in you that will be hard to break.

3. Make a commitment. Learning a language is a commitment. Treat it like a relationship you have with… yourself! In a relationship, you will need to spend quality time together, you will have fights and arguments, you’ll make up and make mistakes. But you will also learn and come out much stronger because of it. One of my favorite things about learning a language is that you’re really competing with yourself, and you only have nothing to prove to anyone except yourself. The most important thing is that you have to commit to one language (or two, if you can handle it), to the studies, the time, and the energy it requires.

4. Set the right expectations. Don’t expect results right away. Just put in the work and team up with the right support system to help you along the way. Language learning is a long-term investment, but it pays dividends. Nice and steady wins the race here. And don’t forget to have fun!

5. Immerse yourself in the cultural context. Movies, TV shows, podcasts, music, books. All that will help you learn about the culture and the language because they will keep you curious, motivated, and engaged.


The American Academy of Sleep Medicine (AASM) said it best: sleep is good medicine. Sleep is just plain good for you. It helps boost your mood, decrease the frequency of illnesses, and improve decision-making.

Even if you can’t learn in your sleep as you had hoped to, sleep can aid you in learning. Don’t just play Spanish or French YouTube videos in your sleep, hoping to learn what you haven’t even studied. Instead, study what you need to study, get a good night’s sleep, and stay motivated. Don’t focus on sleep learning. Focus on learning and sleeping.

That’s it for now. I’ll let you sleep on it. 


Share this article with your network :

Learn a new language with Diáfano

Tell us a little bit about what you're looking for with this quick form. We will be in touch soon.

* indicates required
expert linguist and language teacher irma cedeno
Irma Cedeno



(48 Reviews)

About Instructor

Irma is a trained linguist, native Spanish speaker, and teacher. She is the founder and CEO of Diáfano.


For those with no prior experience with Spanish. 9-week course.

For those who can hold a minimal conversation in Spanish, ask for directions, etc.

For those who are conversational and can express emotions in Spanish

For those who are conversational and can express emotions in Spanish. The course is designed to get you to full fluency.

Upcoming Courses

May 1st - May 30th
Advanced Beginner
May 1st - May 30th
May 1st - May 30th
May 1st - May 30th