Spaced repetition for language learning: a practical guide

You learned the Italian word finestra yesterday.

Today, you still remember that it means "window."

Next week? Maybe.

Next month? You're less certain.

That's one of the challenges of learning a language. Understanding a word during a lesson is relatively easy. Remembering it weeks or months later takes more work.

But what if you didn't have to decide when to review every word yourself?

That's the idea behind spaced repetition, a learning technique that helps you revisit information over time rather than concentrating all your practice into one session.

It's particularly useful for building vocabulary in Spanish, Italian, French, and other languages.

And once you understand how it works, you can use it with flashcards, language-learning apps, or even a simple notebook.

What is spaced repetition?

Spaced repetition is a method of reviewing information across multiple sessions, with time between reviews.

Instead of studying a vocabulary word repeatedly in one sitting, you return to it later.

For example, imagine you're learning the Spanish word olvidar, meaning "to forget."

You might:

• Learn it today.
• Review it tomorrow.
• Test yourself several days later.
• Encounter it again the following week.
• Revisit it after a longer break.

The idea is simple: give your memory repeated opportunities to retrieve information over time.

An illustrative comparison of how five reviews might be distributed.

Cramming: five reviews in one sitting

12345Today

All five reviews happen today.

Spaced practice: five reviews over time

1Today2Tomorrow3Day 44Next week5Later

Reviews are separated by time. Actual intervals vary with the learner and the material.

These intervals don't have to follow an exact pattern. Different words may need different amounts of practice.

A difficult word might return soon, while one you remember easily can wait longer.

That makes spaced repetition particularly useful when you're accumulating vocabulary over months or years.

Why does spaced repetition work?

When you first learn a word, remembering it may feel easy because you've just seen the answer.

But that immediate familiarity doesn't guarantee you'll remember it later.

As time passes without reviewing or encountering the word, recall can become more difficult.

Spaced repetition addresses this problem by spreading review sessions across time.

Each review gives you another opportunity to retrieve the information and strengthen your ability to remember it later.

Research supports the general approach.

A major 2006 review by Nicholas Cepeda and colleagues examined hundreds of experiments involving distributed practice. The researchers found that spreading learning across multiple sessions generally benefits long-term retention compared with concentrating practice together.

A 2022 meta-analysis by Su Kyung Kim and Stuart Webb examined spaced practice specifically in second-language learning. It found meaningful benefits, particularly for retention measured after a delay.

The practical takeaway: reviewing vocabulary over time is usually more useful for long-term memory than cramming the same material into one session.

That doesn't mean every word must follow the same review schedule. The timing depends on how well you remember it and when you want to be able to recall it.

Spaced repetition vs. ordinary flashcards

Traditional flashcards can be useful, especially when they encourage you to remember an answer before turning over the card.

But there's an important difference between using flashcards randomly and using a spaced-repetition system.

Imagine you have 100 Spanish vocabulary cards.

With ordinary flashcards, you might work through the entire collection every evening.

That means spending time on words you already know just as often as words you repeatedly forget.

A spaced-repetition system organizes reviews according to how well you're remembering each item.

You don't need specialized software to use spaced repetition.

However, once your vocabulary grows to hundreds of words, an app can make the scheduling considerably easier.

How often should you review vocabulary?

This is one of the most common questions about spaced repetition.

Should you review a word after one day? Three days? A week? A month?

There isn't one perfect schedule for every word or learner.

Some methods use expanding intervals, where the time between successful reviews gradually increases.

For example:

Day 1 → Day 2 → Day 5 → Day 12 → Day 30

That can be a useful starting illustration, but it isn't a scientifically mandated formula.

In practice, your review schedule should respond to how reliably you're remembering the vocabulary.

Suppose you're reviewing three Italian words:

Finestra — window

You recall the meaning immediately, several times in a row.

You may not need to review it again tomorrow.

Dimenticare — to forget

You hesitate and struggle to remember the translation.

This word probably deserves another review sooner.

Asciugamano — towel

You can't recall the meaning at all.

You'll likely benefit from seeing the answer again, then trying another recall attempt after a shorter interval.

The principle is to avoid spending unnecessary time on familiar vocabulary while giving difficult words more attention.

You should also remember that a longer review interval isn't automatically better. Waiting too long can make recall unnecessarily difficult.

A well-designed schedule balances the benefits of spacing against the risk of forgetting.

Spaced repetition works best with active recall

Spacing your reviews is useful. But what you do during those reviews also matters.

Consider two ways of practicing the French word la fenêtre, meaning "the window."

Method A: Rereading

You look at la fenêtre and its English translation five times.

Method B: Active recall

You see la fenêtre and try to remember the English meaning before revealing it.

Later, you reverse the question and try recalling the French word for "window."

The second method requires more effort because you're actively retrieving information from memory.

That effort can support stronger long-term learning.

Research involving foreign-language vocabulary has found substantial benefits from repeated retrieval practice compared with simply restudying material after it has been learned.

For practical language learning, it's helpful to combine spaced repetition with different forms of recall:

• Recognizing the meaning of a foreign-language word.
• Remembering the foreign-language word from its English meaning.
• Spelling the word without hints.
• Saying the word aloud.
• Identifying it in a spoken sentence.
• Using it in a meaningful expression.

These activities don't all test exactly the same skill. Combining them can help build a more useful understanding of vocabulary.

A practical spaced-repetition routine for language learning

You can begin without buying flashcards or downloading another app.

Choose five words you're currently learning.

For example:

Here's a manageable routine.

Step 1: Learn the words in context

Read each word, listen to its pronunciation if possible, and learn a short example sentence.

For vorrei, you might use:

Vorrei un bicchiere d'acqua.

"I would like a glass of water."

Step 2: Test yourself later

After some time has passed, look at the Italian words and try recalling their English meanings.

Then reverse the exercise.

Can you remember the Italian for "the street" without seeing la strada?

Step 3: Separate familiar and difficult words

Keep track of which words you recalled easily and which ones required help.

You don't need a complicated scoring system.

Even two categories—"remembered" and "needs practice"—are enough to begin.

Step 4: Review difficult words sooner

Return to the words you struggled with after a shorter break.

Allow familiar words a longer interval before reviewing them again.

Step 5: Keep older words in circulation

As you introduce new vocabulary, don't abandon the words you've already learned.

Continue reviewing them occasionally, even after several successful recall attempts.

The objective is to build a vocabulary collection that remains useful over time.

What should you do when you forget a word?

Forgetting a word during spaced-repetition practice doesn't mean the method has failed.

It means you've discovered something that needs more attention.

Suppose you're asked what dimenticare means, and your mind goes blank.

Here's what to do:

Reveal the answer. Confirm that it means "to forget."

Reconnect the word with context. Read or create a sentence using it.

Non voglio dimenticare.

"I don't want to forget."

Try retrieving it again. After a brief break, see whether you can recall the meaning without looking.

Schedule another review sooner. Don't treat the word as mastered simply because you've now seen the answer.

Most importantly, don't turn every forgotten word into a frustrating experience.

The purpose of review is to identify what needs practice, not to achieve a perfect score every time.

Three common spaced-repetition mistakes

1. Learning more words than you can reasonably review

It's tempting to add 20 or 30 new words to your collection every day.

But every new word potentially creates additional reviews in the future.

If you introduce vocabulary faster than you can maintain it, the review workload can become overwhelming.

A smaller, sustainable daily target may be more effective for your routine.

2. Only practicing recognition

Choosing the correct translation from four options is useful, but it isn't the same as producing the word independently.

If your goal includes speaking or writing, make room for exercises that require you to recall words without seeing the answer.

3. Stopping reviews after one correct answer

Remembering a word today doesn't guarantee you'll recall it next month.

Continue checking familiar vocabulary across longer intervals rather than permanently removing it from practice.

Can you combine spaced repetition with Duolingo?

Absolutely.

You don't need to choose between spaced repetition and structured language lessons.

If you're learning Spanish through Duolingo, for example, you can continue using its lessons and review activities while reinforcing vocabulary separately.

A useful routine might involve completing a language lesson, learning or revisiting a few words, and testing your recall later.

The same idea applies if you're learning through Babbel, classroom lessons, a tutor, or independent reading.

Spaced repetition isn't a competing language-learning philosophy.

It's a technique you can incorporate into almost any learning routine.

How OneWord uses spaced repetition

OneWord is designed around a simple principle: learning a new word is only the beginning.

Each day, you're introduced to one new word in Spanish, Italian, or French.

You discover its meaning, hear its pronunciation, and see how it's used.

Then OneWord helps reinforce vocabulary through several complementary features.

Adaptive reviews. Previously learned words return over time. Words you struggle with receive more attention, while familiar words can go longer between reviews.

Notification quizzes. Certain review questions can be answered directly from your iPhone notifications without opening OneWord.

Word Gate. An optional feature that presents brief vocabulary questions before you continue into selected apps like Instagram or TikTok.

Varied practice. Matching, spelling, speaking, listening, and other exercises let you encounter vocabulary in different ways.

Stories. New words gradually unlock lines in unfolding conversations, connecting vocabulary to meaningful situations.

The goal isn't to make you spend more time studying.

It's to help useful vocabulary remain part of your memory through manageable moments of practice. See how it works.

Is spaced repetition enough to learn a language?

Not by itself.

Spaced repetition can be highly useful for remembering vocabulary, but language ability also involves grammar, listening comprehension, pronunciation, conversation, reading, and understanding how expressions change across situations.

A good learning routine includes opportunities to use language naturally.

Read something interesting. Listen to people speaking. Practice having conversations. Learn grammar when you need it.

And use spaced repetition to help retain the vocabulary you encounter along the way.

The goal is to remember words when you need them

You don't need to memorize every Spanish, Italian, or French word in one sitting.

You also don't need to review every word every day.

What matters is returning to vocabulary often enough to strengthen your ability to remember it over time.

Learn it. Try to recall it. Revisit it later.

And as the word becomes more familiar, give it space.

The goal of spaced repetition isn't to make studying endless. It's to help what you've learned remain useful long after the lesson ends.

Research and further reading

• Kim, S. K., & Webb, S. (2022). The effects of spaced practice on second language learning: A meta-analysis. Language Learning.
• Cepeda, N. J., et al. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin.
• Karpicke, J. D., & Roediger, H. L. (2008). The critical importance of retrieval for learning. Science.