Review algorithm

Spaced repetition

Memory works such that forgetting begins the moment you meet a new word, and every successful recall slows it down. Spaced repetition catches a word just as it is about to slip away: that is where a review does the most good, while an earlier one does almost nothing.

Recalling beats re-reading

Looking at a word next to its translation creates a feeling of knowing — but that is recognition, not command of it. What leaves a real trace is effort: trying to produce the meaning yourself before it is shown. That is why learning here is built on exercises rather than on scanning lists.

It also explains why some reviews feel hard. An easy review gives you almost nothing: if the word surfaced instantly, the moment was chosen too early.

Why the intervals grow

Every successful recall strengthens the trace, which means the next encounter can be pushed further out. A word you have confidently recalled several times returns in weeks rather than the next day — freeing your time for whatever is genuinely shaky.

The reverse holds too: a mistake means the interval was too long, so the word comes back much sooner. The schedule keeps adjusting to you rather than to an average.

What this buys you over time

Your dictionary grows while the daily load barely does: the better you know a word, the more rarely it returns. That is what makes it possible to keep hundreds of words active while spending the usual few minutes a day.