You looked the word up on Tuesday. On Saturday it is gone. You look it up again, feel briefly annoyed at yourself, and the cycle repeats — some words you have looked up more than twenty times.
This is not a memory defect. It is how forgetting works, and it is predictable enough to be exploited.
The forgetting curve, briefly
Memory for a new item decays fast at first, then slows. A word you meet once is mostly gone within days. But every time you successfully recall it just as it is fading, the decay gets flatter — the same word now survives a week, then a month, then a year.
The practical consequence: when you review matters more than how long. Ten reviews spread across a month will beat an hour of cramming, and take less total time.
What spaced repetition does
A spaced repetition system tracks how well you knew each word and schedules its next appearance accordingly. Words you find easy disappear for weeks. Words you keep missing come back tomorrow. You never choose what to review, which removes the part of studying where you accidentally practise what you already know because it feels nice.
How to build a deck that is worth reviewing
Most abandoned decks were badly built, not badly reviewed.
- Add words you met, not words from a list. A word from a conversation you had arrives with a hook attached — where you were, what you were trying to say. A word from “500 Essential Nouns” arrives with nothing.
- Cap the daily new cards. Ten a day is plenty. Every new card is a small debt of future reviews; add a hundred today and next week collapses.
- Save phrases, not bare words. *”It is worth it”* is more useful than *worth*, because you can say it immediately without assembling anything.
- One meaning per card. A card with four translations on it is four cards pretending to be one, and you will fail all of them together.
- Add a sound. If you only ever meet a word in writing, you will not recognise it when spoken at full speed.
- Delete ruthlessly. If a card has annoyed you five times and you still do not care about the word, remove it. A deck you avoid teaches nothing.
How long per day
Fifteen minutes is enough. Flashcards are a maintenance tool — they hold vocabulary in place so that the real work, which is speaking, has material to use. Anyone spending an hour a day on cards and no time talking has built a very well-organised collection of words they cannot deploy.
A sensible split: fifteen minutes of cards, and whatever time you have left goes to conversation.
Recall, not recognition
The most common way to waste review time is to look at a card, think *yes, I know that one*, and flip it. That is recognition, and it is far easier than what you need.
Before flipping, say the word out loud, in a sentence. If you cannot produce it, you do not know it — no matter how familiar it looks. Producing under mild pressure is the skill that transfers to conversation; recognising is not.
Where flashcards fit in the week
Cards are the memory layer, not the learning layer. The order that works:
1. Meet a word in a real context — a conversation, a roleplay scene, something you read. 2. Add it the same day, in a phrase, with sound. 3. Review it when the system asks, out loud. 4. Use it deliberately in your next conversation.
Step four is the one people skip, and it is the one that converts a card you can pass into a word you own. When you have ten minutes and no energy for cards, a word game keeps recall warm with less effort.