How VocabFreak works: frequency order + spaced repetition

No black box. VocabFreak rests on two well-studied ideas — learn a language's most frequent words first, and review each one right before you'd forget it. Here's exactly how that plays out, including what it means for a word to count as “learned.”

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1. The most common words, first

A tiny slice of any language does most of the talking. This is Zipf's law: the ~1,000 most frequent words cover roughly 80% of everyday speech. Learn words in frequency order and you buy the most comprehension per hour studied — you start understanding real sentences almost immediately, instead of memorising vocabulary you'd meet once a year.

But which frequency list matters. A newspaper corpus over-teaches government and municipality and skips you and thanks; a movie-subtitle corpus over-teaches kill and weapon. VocabFreak ranks words with wordfreq, a blend of subtitles, web text, news and Wikipedia — so the order reflects real everyday usage, not one register's bias.

Tiers: depth where it counts

The most frequent ~2,000 words get full cards — multiple examples, the spoken form, and (for Finnish) a spoken conjugation table. Beyond that, deeper words are lighter recognition cards. You spend your effort where it returns the most.

2. Spaced repetition: the four buttons

Every time a word comes up, you rate how well you recalled it. That rating reschedules the card:

The idea (the spacing effect): recalling something just as you're about to forget it is what moves it into long-term memory. So correct answers push the next review further out — a day, then a few days, then weeks, then months — and each word surfaces right when it's about to fade.

3. The exact schedule

New cards follow fixed early steps, then grow by a personal ease factor (starts at 2.5, and every word carries its own):

“×ease” means the previous interval is multiplied — so a word you keep getting right stretches out fast (e.g. 6 → 15 → 37 days …). A “Good” or “Easy” nudges that word's ease up; “Hard” nudges it down; “Again” drops it by 0.2 and sends the word back to the start (with a floor of 1.3, so nothing spirals). Under the hood this is a lightweight version of the classic SM-2 algorithm.

4. When is a word “learned”?

This is the number on your profile, so here's the precise rule:

Why 7 days? To reach a 7-day gap, you have to have recalled the word correctly several sessions in a row — the scheduler only stretches an interval that far once you've repeatedly proven you know it. A word that's still bouncing around at 1–4 day intervals isn't secure yet, so it doesn't count. Cross the 7-day line and it's genuinely settling into long-term memory. (Miss a “learned” word later and it simply drops back below the line until you rebuild it — the count reflects what you actually still know.)

5. Your estimated level

Your level is a rough CEFR estimate based on how many words you've learned (by the rule above), since vocabulary size tracks closely with comprehension:

It's an estimate, not an exam — a motivating sense of where you stand, calibrated to frequency-ranked vocabulary.

6. Daily pace: why new words are capped

You choose how many brand-new words enter rotation per day — Chill (5), Steady (10), Standard (20) or Intense (30). Reviews of words you've already met are never capped; only new ones are. That's deliberate: every new word becomes a growing tail of future reviews, so adding too many at once buries you in reviews a week later. A steady trickle keeps the daily load sustainable and the retention high.

7. The placement test (skip what you know)

Already know some of the language? A short multiple-choice test (up to a dozen questions) does a binary search across the frequency list to estimate your level, then marks the words below it as already learned — so you start where you actually are instead of at word #1.

8. Streaks and activity

A day counts as “studied” the moment you review one card — you don't have to clear all your reviews or finish your new words. That low bar is deliberate: a two-minute daily habit that survives busy days beats an all-or-nothing goal you abandon the first time life gets in the way. Your streak is the run of consecutive days you've shown up, and the activity heatmap shows your history at a glance.

Optional reminders (toggle them per language in your profile) send a gentle nudge each morning and evening, in your local time — and only on days you haven't studied that language yet, so you're never nagged after you've already practised.

Frequently asked questions

What does “learned” mean here?

A word is counted as learned once its next review is scheduled 7 or more days out — which only happens after you've recalled it correctly several times in a row. It's the basis of your “words learned” total and your estimated level.

How does the spaced repetition decide timing?

Each rating reschedules the card: correct answers push the next review further into the future (a day → a few days → weeks → months), while “Again” resets it to about a minute. You end up reviewing each word right before you'd forget it.

How many words until I'm fluent?

Comprehension climbs fast early: ~1,000 words covers most everyday speech, and 2,000–3,000 gets you comfortable in most conversations. The full deck takes you toward B2–C1 territory.

Start learning — the most common words, spaced so they stick →

See also: the 1000 most common Finnish words · spoken Finnish (puhekieli) · what's new · open the app · privacy