Spaced repetition explained: remember vocabulary for good
You learn twenty new words on Monday. By Friday you remember six. It isn't a problem with your memory; it's how human memory works. The good news is that there's a well-researched technique that makes vocabulary stick with far less effort: spaced repetition.
The forgetting curve
In the 1880s the psychologist Hermann Ebbinghaus measured how quickly he forgot lists of nonsense syllables. He found that memory drops steeply in the first hours and days after learning, then levels off. Without review, most of what you learned today will be hard to recall within a week.
But he also found something more useful: each time you successfully recall something, it fades more slowly afterwards. A word you've remembered three times, at growing intervals, can last for months.
How spaced repetition works
Instead of reviewing everything every day, you review each item just before you're likely to forget it. Easy items come back rarely; hard ones come back often. A typical sequence of intervals looks like this:
| Review | Interval after the previous one |
|---|---|
| 1st | same day or next day |
| 2nd | about 3 days |
| 3rd | about 1 week |
| 4th | about 2–3 weeks |
| 5th | about 2 months |
If you forget a word at any point, its interval resets to short and it climbs again. Software keeps track of all of this for you, which is why spaced repetition is usually done with flashcard apps.
Why it's so efficient
- You stop over-reviewing words you already know.
- Effortful recall strengthens memory. Retrieving a word that's slightly hard to remember (the testing effect) builds a stronger memory than re-reading it.
- Daily reviews stay short. Five minutes a day can maintain thousands of words once the system is running.
How to make good cards
- Learn words in context. Put the word in a short sentence: Me pone un cortado, por favor beats cortado = coffee with milk.
- One idea per card. Split complex cards into several simple ones.
- Include the article or gender for nouns: die Zeitung, not Zeitung.
- Say the answer out loud before you reveal it. It trains pronunciation as well as memory.
- Be honest when you grade yourself. Marking a half-remembered word as easy only makes it come back too late.
- Add words you actually met. Words from your own conversations and reading are far easier to remember than lists from a book.
Spaced repetition in 2Lingua
In 2Lingua, the vocabulary garden is a spaced-repetition system. Words from your conversations, stories and podcasts are added with the sentence where you met them. Each review asks you to recall the word, and how well you remember it decides when it comes back. The garden's plants grow as your words move into long-term memory.