Retention: Remembering What You’ve Learned

By Jonty Yamisha • 13 minute read

Remembering What You’ve Learned

Language learning is work, and when we work hard, we want to know we’re getting the most bang for our buck. 

How can we learn most efficiently? This brings up two issues: how can we best retain what we’ve learned, and how quickly can we integrate new material?

Retaining What You’ve Learned

To make your learning most efficient, we’ll look at how to study, the need for sleep, what makes us forget things, and how to improve our recall.

Cramming Doesn’t Work

Think back to your school days. Remember studying for an exam?

After weeks of assuring yourself you have plenty of time, the all-important final exam looms tomorrow. 

You had planned to start early. You sketched out a study calendar weeks ago. Where is it now? You curse yourself for your shameless procrastination. Your only alternative is to turn off your phone, order a pizza, brew a pot of coffee, pull an all-nighter, and hope for the best.


Unfortunately, science proves cramming doesn’t work.

The best way to master new material is to take it in small, digestible bites over a few weeks or months. Each time you return, your brain recognizes the material and snaps to attention. It reinforces the knowledge so you can remember it.

In a study at the University of California, results showed that for 90% of participating students, learning over time was more helpful than cramming.

However, over 70 percent of students insisted that cramming had been more effective. How were they tricked into believing that? 

It’s because people are creatures of habit. The more familiar a study method is, the more likely you’re to believe it works. Cramming doesn’t work when studying for an exam, and it doesn’t work for language learning, either. 

Regular study sessions are key.

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Familiarity ≠ Mastery

If you’ve always made flashcards, highlighted pertinent material, or learned by rote, you’ve convinced yourself you can’t learn any other way. 

None of those methods are necessarily bad, but just because they’re familiar, there’s no guarantee you’re learning and retaining new material.

Here’s an example. After a long cramming session, you might listen to some recordings, take notes, or make flashcards. This study approach may feel like a well-worn security blanket. It’s what you grew up with in high school or college. You might even retain several phrases or sentences with this approach.

In the short term, you could start feeling confident or even smug. You can’t wait to show your newfound fluency to a friend or a loved one.

school friend

However, when it comes time to demonstrate your mastery, you choke. 

Maybe the word or phrase is on the tip of your tongue and won’t come out. Maybe it’s buried deep in your mind, and you can’t recall it. Maybe an entirely different word or phrase keeps popping into your mind.

What the heck happened here? In short, just because the information is familiar doesn’t mean you’ve mastered it. Here’s why. The highlighted texts and flashcards become familiar because they’re processed through sensory areas, such as the visual cortex. 

Comprehension and recall are supported in entirely different areas of the brain. The frontal cortex and temporal lobe, for example, create memories as knowledge is revisited and built upon. Memory is a coordinated effort occurring throughout the brain.

Metacognition is how we evaluate our brain’s performance, and research shows most of us aren’t particularly good at it.

Retention Requires Sleep

One common misconception is that actively thinking about learning something—putting our minds to it, so to speak—will help us recall it. 

Being alert is commendable, but scientists know reorganizing new information and providing structure and context is more beneficial for retention.

You can and should lay out your new language in a way that makes sense to you, but then your brain does much of the work for you. Surprisingly, one of the most important brain functions occurs while sleeping.

Retention Requires Sleep

Every random bit of knowledge picked up during the day gets categorized and sorted in order of priority during rest. Everything learned is filed in a nice, tidy cabinet organized by date and importance.

During sleep, your brain keeps you from obsessing over the nouns, verbs, and tenses you already know and instead helps that complex new piece of information you learned take firm root.

So whatever you do, get plenty of sleep. Sleep is crucial to overall good health, as it prevents many serious diseases. 

Moreover, it makes exercise more beneficial, keeps off excess weight, and helps us manage stress. Those advantages are well worth getting quality rest, but sleep’s greatest benefits pertain to learning.

For far too long, our society has treated sustained sleep as a form of laziness that serious students and businesspeople should avoid. The smartest guys in the room don’t linger in bed when they could be at their desks closing big deals at 6 a.m., right?

Nothing could be further from the truth. Trying to learn anything new without getting adequate sleep is an exercise in futility. Sleep is strongly linked to learning, comprehension, and retention of new knowledge.

Here are the accounts of three revealing experiments.

1. Sleep Consolidates and Relocates Existing Memories to Make Room for New Ones

Researchers at the University of California studied the role of sleep spindles in cognitive performance. Sleep spindles are sudden bursts of brain activity in the second stage of light sleep.

The experiment began at noon when the 44 recruited students had to memorize 100 names and faces. When their study time was up, they were immediately tested.

sleeping student

Half the participants then took a 90-minute nap. Scientists measured their brain activity while they slept. While the other participants stayed awake.

Six hours later, both groups were assigned 100 new names and faces to memorize. All were tested on their recall.

The students who had stayed awake all day performed significantly worse on their 6 p.m. test than on their 12 p.m. test. The students who had napped, on the other hand, did approximately 10 percent better on their second test. Clearly, our ability to learn is compromised as the day wears on, and sleep provides a much-needed memory boost. 

That’s because sleep spindles transfer new, relevant memories from deep in the hippocampus to the prefrontal cortex, freeing up space for all the new information that will pour in tomorrow. It’s a little like organizing a storage unit to fit many more items inside.

The more you sleep, the more sleep spindles you have, and the more you learn and remember.

2. Sleep Increases Motor Skills

Sleep Increases Motor Skills

Each student was assigned a sequence of five single-digit numbers to repeatedly type in order on a computer keyboard. This task sounds simple enough, but the results were less than impressive.

After a good night’s sleep, the participants were retested. The average improvement on the morning test was 20% in speed and a whopping 39% in accuracy.

This point is important because speaking a language requires your brain to develop new motor skills associated with quickly and easily pronouncing new words and phrases.

3. Sleep Makes You Less Forgetful

Sleep Makes You Less Forgetful

John G. Jenkins and Karl M. Dallenbach, two pioneers in the study of sleep and memory, performed a groundbreaking experiment in 1924.

Test participants were taught nonsense syllables. Every hour, they were asked to remember as many of the gibberish syllables as they could. Half the participants stayed awake all day for the study, and the other half slept. Someone woke them up every hour and tested their recall.

As the day went on, the participants who stayed awake gradually forgot their syllables. The students who slept were somewhat forgetful in the first few tests, but their memories eventually stabilized until they could perfectly recite their syllables.

The experiment proved sleep helps keep newly learned information intact.

When learning a new language, it’s tempting to cram all you can into long, focused sessions. However, science proves you’re better off hitting the sack and letting your brain do the heavy lifting.

Fight the Forgetting Curve

Now, you know how important sleep is to learning. But what about that evil enemy of learning called forgetting?

Fight the Forgetting Curve

You’ve probably been there. You had it down perfectly just a week ago. 

After two hours of focused study, the Italian, Swedish, or Japanese rolled fluently off your tongue. Had you immediately landed on foreign soil, you could have bantered with the natives as though you’d known them all your life.

What Happened?

It hardly seems fair, but almost nothing roots firmly in your brain the first time you learn it. It’s a real and rather depressing fact of life. If knowledge isn’t reinforced, it’s lost over time.

On the bright side, life would be awfully dull without learning challenges. No one would get excited about new inventions, breakthrough medicines, or space exploration.

Fortunately, your sense of accomplishment when you permanently master that new language will be well worth your efforts. All you have to do is fight the forgetting curve.

Discovering the Nature of Memory Loss

Hermann Ebbinghaus was a 19th-century German psychologist and a pioneer in the experimental study of memory. 

He must have been a real glutton for punishment. Basing his research on spaced learning, he tested his own memory over various periods and plotted the data. His resulting graph looks something like the architectural drawing for a steep slide at a water park.

Just one day after learning something new, your memory of it is only slightly better than 50%. The downward slope is less dramatic after the first couple of days, but by the seventh day, retention is less than 20%.

Ebbinghaus dubbed this the forgetting curve, a reliable prediction of the rate of memory loss over time. Once he’d gathered all the data from his spaced learning studies, he plotted it on a graph that looked something like the image below.

the forgetting curve

Now, it bears highlighting that Ebbinghaus didn’t invent this graph. Rather, it illustrates the point his research proved. Information you study fades over time based on two things: the strength of the memory and the passage of time.

The Strength of the Memory

Strong memories are easier to recall than weaker ones. That said, memory is subjective. Who can measure a memory’s strength?

In language learning, we benefit from this fact by knowing that whatever we can do to strengthen our learning experience helps us retain the information more easily.

Some examples include:

  • Use media
  • Involve what we enjoy 
  • Make learning relational 
  • Move facts from our passive memory to active memory 

The Time That Has Passed Since Ebbinghaus

Research done after Ebbinghaus’s has shown learners forget an average of 90% of what they learn within the first month of learning it. 

While this statistic may vary for one piece of information versus another, think of it as an average. If you were to memorize 100 foreign language vocabulary words and then ignore them a month later, you’d only remember 10 words.

How to Improve Your Recall with SRS

Now that we know how memory works, we can do something about it! Here are a few ways you can leverage spaced repetition to improve recall.

1. Spaced Learning

Everything you’ve read in this section has been a lesson in the value of a spaced repetition system, or SRS.

An SRS is any technique incorporating increasing intervals between subsequent reviews of previously learned materials. Physical flashcards are among the earliest forms of SRS, and today, SRS is built into many modern language-learning software.

For the past decade, I’ve worked as an endangered language activist, laboring to preserve and promote my ethnic language, Circassian.

I’m not the only person interested in this topic, but I’m probably the most motivated guy in the field for one simple reason: if I fail, my language will die, and my cultural heritage will fade from existence.

Over those ten years, I’ve cut the time it takes to learn a language in half. Unsurprisingly, the key is SRS.

Here’s a quick summary of how SRS works. On the first run-through of new content you’re learning, you review and mark any items you don’t recall. Whenever a new memory begins to fade, you re-energize it by refreshing and strengthening your memory.

combining the forgetting curve

Every time after that, the SRS system works its magic. In the second review session, the system only asks you to remember the stuff you forgot last time.

As the earlier example noted, without revisiting your study notes, on average, you’d forget 90 of those 100 words you memorized, but that’s just an average. Each word has its unique forgetting curve, and some are longer than others.

2. Intelligent Scheduling

SRS is clever. It doesn’t merely keep track of what you forget and remember. It also predicts when you’re most likely to forget things based on an algorithm that gathers information about you as you study. 

It can then intelligently schedule items to be reviewed at the most efficient time possible: just before you forget them.

So whenever you use SRS, it reveals what you should be studying, freeing you to focus entirely on studying. The system handles all the scheduling and arranging for you.

3. Digital Flashcards

Early SRS systems were implemented with physical flashcards. This was a huge step up from rote learning, but I couldn’t quite take advantage of the full implications of SRS.

Now, with SRS software, the computer not only handles all the calculations but does so in incredible detail. It considers a wide array of information to optimize your study time.


That means you achieve more in the same time, or spend less time and don’t fall behind in your studies.

The applications of this for language learning are obvious. Place the content you’re learning into the SRS, spend some time daily, and let the software handle the rest.

The Limits of SRS 

Although SRS can be very powerful, it’s not a language-learning method—just a tool you should incorporate into your broader efforts. 

Many learners overestimate what SRS can do when they first discover it. I was a classic example of this. It’s easy to get into the mindset that you must mindlessly add things to the system, and you’ll magically learn it. Ultimately, you still have to put in the hours to acquire your new language—SRS just makes it more efficient. 

However, it’s tempting to add too many vocabulary words too quickly, making your reviews tedious and time-consuming. Keep the content in your SRS trimmed to a minimum unless you want to put in hours daily.

Also, remember that your brain is extremely good at learning in context. Many people find that, although you can easily remember an item when reviewing it in the SRS system, when it comes to using it in real life, it’s not as easy. 

This is why no matter how good your review system is, you still need to get out there and use the language. Ultimately, SRS is a powerful and effective tool—but’s not a comprehensive learning system.

Jonty Yamisha

Husband, father, and accidental polyglot Jonty Yamisha founded OptiLingo after working to protect his native language, Circassian, from extinction. He has helped thousands finally achieve their dream of reaching fluency by promoting SPEAKING over typing languages with OptiLingo.