How to learn vocabulary with flashcards that stick

Vocabulary is the purest case for spaced repetition there is. A word is a small, discrete fact; a language has tens of thousands of them; and you need them not for a test next week but for a conversation next year. Every one of those properties is exactly what the spacing effect rewards. Learners who “just can’t remember words” almost never have a memory problem — they have a scheduling problem, and flashcards done right solve it.

Here is how to make vocabulary cards that actually stick, and how to keep the habit sustainable.

Why vocabulary fits spaced repetition so well

Grammar is a system you can reason through; vocabulary is not. There is no rule that tells you the word for “kitchen” — you either retrieve it or you do not. That makes retrieval practice, the testing effect, the whole game. And because words are forgotten on a predictable curve, a scheduler can bring each one back at the last useful moment instead of forcing you to re-run the whole list. Tens of thousands of small facts, each reviewed only when it needs to be: that is what a spaced-repetition app is for.

Write cards that stick

The card, not the app, decides whether a word sticks. Three rules do most of the work. One word per card — a card that asks for five words teaches none of them. Add a context sentence, ideally one you wrote or met yourself, because a word anchored to a situation is retrieved far more easily than a word floating alone. And where a meaning is concrete, an image beats a translation: a picture of the thing skips the detour through your native language. Keep the answer side short; you are testing recall, not reading.

Use reverse cards

A card that shows the foreign word and asks for the meaning trains recognition — reading, listening. A card that shows the meaning and asks for the foreign word trains production — speaking, writing. These are different skills, and most learners only ever train the first, which is why they understand far more than they can say. Reverse cards fix that: one entry, two directions. Learn a word in both, and it becomes usable rather than merely familiar.

How many new words a day?

There is no magic number, and be suspicious of anyone who gives you one. What matters is that new cards come at a rate you can sustain every day, because every new word you add today creates reviews tomorrow, next week and next month. Start small and watch the forecast: if the reviews due over the coming days look heavier than the time you actually have, add fewer new words for a while. A steady trickle you never miss beats a burst you abandon. The scheduler handles the reviews; your only decision is the pace of new material.

Recall, do not just recognise

The moment of effort — staring at the card and pulling the word out of memory — is where the learning happens, so do not shortcut it. Say the word out loud before you flip the card. Rate yourself honestly: “again” when it would not come, “hard” when it came slowly, “good” when it came, “easy” when it was instant. Honest ratings are how the scheduler learns your memory; flattering ones just bring the word back too late.

Build cards from what you are actually reading

The best vocabulary is the vocabulary you meet. Paste a paragraph from an article you are reading, drop in a link, or dictate the words you just heard in a conversation, and turn them into cards while the context is fresh. If you are starting a topic from scratch — food, travel, a professional field — let AI draft a first set of cards from the topic and then edit them into your own words. Cards you have touched stick better than cards you merely imported.

How Repeto fits

Repeto is built for exactly this workflow. Write cards in the editor with images, tags and reverse cards; import from pasted text, a web link, a PDF, a scan or dictation; or draft a starter set from a topic with AI. The FSRS scheduler brings each word back right before you would forget it, and the daily goal, streak and review forecast keep your pace visible so new words never bury you. Everything you need for vocabulary — learning, the scheduler, your own cards and sync between iPhone and iPad — is free without limits; only AI generation uses credits, as a one-time purchase that never expires. For a broader checklist, see what to look for in a spaced-repetition app, and for how the scheduling works, our FSRS guide.

Pick the words you actually meet, give each one a card and a context, learn them in both directions, and let the schedule do the remembering.