A 140-year-old experiment, a German psychologist, and a quietly powerful algorithm that explains why ten minutes a day beats a weekend cram — every time.
Hermann Ebbinghaus memorized over 2,000 nonsense syllables and tracked exactly when he forgot them. The shape of that curve has survived a century of replication — and it explains why your high-school French is gone.
The bad news: within 24 hours about half of what you have just learned is forgotten. By the seventh day, four words out of five are gone — even if the lesson felt easy.
The good news: a single, well-timed review resets the curve. After the third or fourth review, the slope nearly flattens. The word is yours.
Drawn from peer-reviewed research on memory, retrieval, and second-language acquisition.
Across 271 published comparisons, spreading the same total study time out beat cramming it together in 259 of them. (Cepeda et al., 2006)
The 2,000 most frequent word families cover about 80% of written text, and more of ordinary conversation. A year of 10-minute sessions gets you there. (Nation & Waring, 1997)
Learners drilled on Swahili–English word pairs recalled 80% of them a week later. Those who only reread recalled 36%. (Karpicke & Roediger, 2008)
Each new word is shown again at progressively longer intervals. After the seventh review, it lives in long-term memory with negligible decay.
| METHOD | TIME / DAY | RETENTION (1 YR) | WORDS LEARNED |
|---|---|---|---|
| Weekend cramming | 0 → 4 hrs (binge) | ~14% | ~280 |
| Classroom (3×/week) | 45 min | ~38% | ~760 |
| Generic flashcards | 15 min | ~52% | ~1,040 |
| SRS (LexyBooster) | 10 min | ~91% | ~2,000 |
Everything else — streaks, leagues, audio — is scaffolding for these three things.
Each word arrives with native audio, IPA, and an example sentence. Single-word flashcards forget faster — context anchors recall.
Four exercise types, multiple-choice, reverse multiple-choice, word-building and typing, all force you to produce the word rather than merely spot it. Production is what makes memory permanent.
Words you almost forgot come back sooner; words you nail get pushed further out. The algorithm tunes to your forgetting curve.
The free plan is forever. Annual Pro starts with 7 free days: exam decks, audio with no limit and speaker choice.