Spaced Repetition for Language Learning
You learned twenty words yesterday and today half of them are gone. That is not a discipline problem, it is how memory works, and spaced repetition is the fix: a review schedule that shows you each word right before you would forget it. This guide explains the science, the Leitner system behind it, and the exact 1/3/7/21 day schedule built into NextLang vocabulary.
Why Cramming Fails
Ebbinghaus mapped the forgetting curve in 1885 and a modern replication confirmed it: without review, most newly learned material fades within days, with the steepest loss in the first 24 hours. Murre & Dros, 2015 (PLOS ONE)
A cramming session feels effective because everything is fresh while you study. But fluency with a word you saw two minutes ago says nothing about whether you will recall it next week at a ticket counter. The forgetting curve drops fast, and one long session gives every word exactly one chance to survive it.
Reviews change the shape of that curve. Each time you successfully recall a word, its memory trace decays more slowly, which means the next review can wait longer. Spacing is not about studying more, it is about placing the same effort where it compounds.
How Spaced Repetition Works
A meta-analysis of 254 studies found that distributed practice reliably beats massed practice: spreading reviews over time improved retention in almost every comparison examined. Cepeda et al., 2006 (Psychological Bulletin)
Look at 'la biblioteca', say the translation out loud, and only then flip to check.
A word you learned today is worth reviewing tomorrow, not ten more times tonight.
A word you have recalled four times in a row only needs a check every three weeks.
Hesitating for two seconds and then getting it right is a better workout than answering on reflex.
The Leitner System
The simplest way to run spaced repetition is the Leitner system, invented by Sebastian Leitner in the 1970s for paper flashcards. Every word lives in a numbered box. Answer correctly and it moves up one box, where reviews are further apart. Miss it and it drops back to the start. Five boxes are enough for vocabulary:
New words and anything you just missed. They stay in rotation until you get them right.
You recalled the word once. See it again tomorrow to confirm it survived the night.
Two successful recalls. The memory is forming, so the gap stretches to a few days.
Three in a row. A weekly check is enough to keep the word alive.
Mastered. The word counts as learned and only returns every three weeks for maintenance.
The demotion rule is what makes the system honest. A word you failed after three weeks clearly was not mastered, so it restarts the climb. No bookkeeping, no formulas to tune: two possible answers per card drive the whole schedule.
A Schedule That Sticks
Common Mistakes to Avoid
Marking words as known out of optimism
A vague 'I think I know this' pushes the word weeks away before the memory is ready. When in doubt, rate it as still learning.
Cramming once a week instead of short daily reviews
Massed practice fades within days. Spread the same total time across the week and far more of it converts into long-term memory.
Only ever recognizing, never recalling
Passively confirming 'yes, I've seen this' is not retrieval. Cover the answer, produce it, then check.
Resetting the whole deck after a pause
Missing a week does not erase your progress. Resume where the schedule left off; words you truly forgot will demote themselves on the first honest review.
Adding fifty new words a day
Every new word is a future review. Add a handful daily so tomorrow's session stays short enough to actually happen.
Spaced Repetition Built Into NextLang
Your NextLang vocabulary runs this exact Leitner schedule for you. Save words while studying generated flashcards or add them by hand, then open a dictionary and press Study: rate each word with Got it or Still learning and the 1/3/7/21 day ladder does the rest. Prefer Anki or Mochi? Every generated deck exports to their native formats, so their schedulers pick your cards up too.
Ready to Make Your Vocabulary Stick?
Save words to your NextLang vocabulary and let the built-in spaced repetition schedule handle the reviews