How to improve your vocabulary in another language
Why the words you study disappear, what spaced repetition does about it, and how to build a five-minute routine that survives past week two.
Almost nobody has trouble learning words. The trouble is keeping them: you look one up, understand it, write it down, and three weeks later none of them are there. That is not a bad memory or weak discipline — most ways of studying vocabulary simply work against how forgetting works.
Why the words you study disappear
Forgetting is not a bug, it is the system. Memory discards by default anything that gives no sign of being useful, and a word seen once gives none. What keeps a word is not how hard you looked at it the first time, but how often you needed it again.
Hence the two classic mistakes. The first is massed study: twenty words in one sitting, all on the same day, none the next. The second is reviewing by reading: running your eyes down the list with the translation beside it, which produces recognition but not recall.
What spaced repetition is, and what it does in practice
Spaced repetition brings each word back just before you would forget it, and stretches the gap every time you get it right. Reviewing what you already know is wasted time; reviewing what you already forgot is starting over. The useful point sits between the two.
Lehrito implements it with SM-2, the algorithm the classic flashcard systems made popular. Concretely:
- The first time you get a word right, it comes back the next day.
- The second time, six days later.
- After that each interval is multiplied by an easiness factor specific to that word: the ones you find easy drift further apart, the hard ones stay close.
- Get it wrong and the interval resets to one day. The word is not lost; it is picked back up.
None of this is yours to decide. When reviewing you only choose between "did not know it", "sort of" and "knew it", and the schedule recalculates itself.
Knowing what you actually know
Every saved word carries a mastery level that rises when you get it right and falls when you do not, grouped into three states you can read at a glance:
- Needs practice
- It does not stand on its own yet. This is where your time is worth spending.
- Learning
- You retrieve it sometimes. A few more reviews to go.
- Mastered
- It comes out effortlessly. It returns occasionally, far apart.
Seeing that distribution changes how you study: you stop grinding the whole list and start attacking only the part that is weak. You can sort your words weakest-first and work down.
A five-minute routine that lasts
- Save as you read, not in collecting sessions. A word that stopped you in a real text has already proved you need it; a "500 most frequent" list has not.
- Save few and good ones. Five a day is 150 a month. Thirty a day is thirty abandoned by Wednesday.
- Review what is due, not everything. When words are due, a banner inside the app tells you how many — that is your session for the day.
- Turn the review into a [game](/en/games). Same review, far less friction to start it.
FAQ
- How many new words should I save per day?
- Five to ten if you study daily. The limit is not how many you can save but how many reviews you accumulate: every new word today is work tomorrow, next week and next month.
- What happens if I stop reviewing for a few days?
- Nothing irreversible. Due words pile up and the algorithm reschedules them as soon as you return; anything you miss goes back to a one-day interval.
- Does spaced repetition work for grammar too?
- It works for anything retrieved from memory. In Lehrito it applies to vocabulary, and there are dedicated gender and conjugation games that drill grammatical patterns using your own words.
- Do I have to pay to use spaced repetition?
- No. Saving and reviewing words is in the free plan, with a cap on saved words. Paid plans raise that cap and unlock extra options in the games.