How many words do you know?

Sixteen yes-or-no questions estimate how many words you already know.

Each answer halves the search over the frequency list. The result reads like “about 2,400 words”, and study starts a little below it.

“An estimate from 16 answers, not a test score. It sharpens as you study.”

no.	rank asked	answer	range
01	20,303	Don't know
02	10,151	Don't know
03	5,075	Don't know
04	2,537	Don't know
05	1,268	I know it
06	1,902	I know it
07	2,219	I know it
08	2,378	I know it
09	2,457	Don't know
10	2,417	Don't know
11	2,397	I know it
12	2,407	Don't know
13	2,402	Don't know
14	2,399	I know it
15	2,401	Don't know
16	2,400	I know it
estimate	≈ 2,400

retained

adj. · words retained · the one number

From then on FSRS-6 schedules every review, and the Today screen reports one number: words retained · 90% threshold. That is the count of words you currently remember with at least that probability.

Day one reads 0: the count holds only what Cognate is keeping for you.

2

grades, Forgot or Knew it.

FSRS-6

one forgetting curve per word.

~20

cards a session, a few minutes.

≤ 2

notifications a day, none when fewer than five words are waiting.

2 years

to the steady state the setup screen predicts.

Every language is a line. Every word is a stop.

Each line is an offline dictionary Tanzi Labs built from open sources, ordered by frequency. It downloads once and then works offline.

Six places outside the app, each doing one thing.

§ widget

Lock Screen and Home Screen. Today's number without opening the app.

¶ watch

A Cognate app on Apple Watch, with the same two grades.

† share

Send a word from any app through the Share sheet.

‡ spotlight

Entries are indexed; search them from the Home Screen.

→ siri

Siri and Shortcuts run Cognate through App Intents.

~ shield, optional

The Screen Time shield keeps the apps you choose closed until today's cards are done.

Nothing leaves your phone.

0

accounts. No sign-up, no e-mail address.

0

trackers. No analytics, no ads, no tracking SDK, no advertising identifier.

0

servers of ours hold your study data. It stays on the device; optional iCloud sync uses your own private CloudKit database, which Tanzi Labs cannot read.

2

network calls in total: the dictionary download from packs.tanzilabs.com, and RevenueCat for subscription status under a random identifier.

0

words sent away for memory hooks or example sentences. Apple's on-device model writes them on supported devices, and the feature can be switched off.

0

app names seen by the shield. iOS hands Cognate opaque tokens for the apps you block.

Read the privacy policy.

The widget, the whole dictionary and search stay free.

Family Sharing on all three. Prices vary by region. The trial converts to a paid year unless canceled at least 24 hours before it ends; cancel any time in Settings › Apple Account › Subscriptions.

Lapsing never takes back what you learned.