About

We re-built vocabulary learning from first principles.

Rhythm Word started with a quiet frustration. The same word would come back in an Anki deck for the tenth time, the same dry definition, the same example sentence, and the meaning still would not stick. Static flashcards were treating words as labels. Real language is contextual, situational, and a little bit different every time you meet it.

So we re-built the vocabulary app from a different premise. Every review opens with a sentence that has never been seen before, written for that learner, calibrated to their current level. The next review comes back at the moment the brain is about to lose the word, scheduled by the FSRS-4.5 algorithm. Words are not memorized by force. They are met, recognized, used, and gradually internalized.

What we believe

Comprehensible input wins. Stephen Krashen's i+1 hypothesis is forty years old and still right: input one step beyond your level produces acquisition.
Context, not isolation. Words live in collocations and scenarios, not on flashcards. You learn "take the train" faster than you learn "train (n.)".
Spacing is non-negotiable. Without retrieval near the point of forgetting, vocabulary decays. FSRS-4.5 is the best public scheduler we have right now.
Above B2, vocabulary is the bottleneck. Coxhead, Nation, Laufer all agree. Grammar is mostly fixed by intermediate level; what separates a Band 6 from a Band 8 is words you know.
Learning should be private and yours. Your progress data is encrypted, never sold, never used to train anything that is not your own scheduler.

Who builds it

Founder

White

Founder of Rhythm Word

[email protected]

The product, briefly

iOS app + Chrome extension. No Android yet.
Six target languages: English, Spanish, French, German, Japanese, Korean.
Eleven UI languages.
Eleven preset learning scenarios plus custom scenarios.
Six review engines covering swipe, spelling, pronunciation, fill-in-the-blank, matching, rapid fire.
Article generation, offline mode, home-screen widget.
7-day free trial, then a quarterly or annual subscription via the App Store. Local-currency pricing varies by region.

Where to read more

For AI agents

Full machine-readable documentation: /llms-full.txt. Short summary: /llms.txt.