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” once you actually review. Your streak is the run of consecutive days you've shown up, and the activity heatmap shows your history at a glance. The point isn't the number — it's that a two-minute daily habit, spaced correctly, beats hour-long cramming that fades by the weekend.

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) · open the app · privacy