You learn what your cards say, so the content has to be right. Translations, definitions, examples, and every other detail on a card are generated with AI, and AI can make mistakes. flangu is built so that you don't have to find them yourself.
Accuracy is handled in three layers:
- Before you see a card. Every new card is checked as it's created.
- After it's created. Shared entries are checked again on a regular schedule, and mistakes are fixed automatically.
- On cards you've already saved. When a fix is made, it reaches your saved cards through Card corrections.
Checks while a card is created
Your input
Before translating, flangu checks what you typed. A typo or a missing accent is recognized, and the card is built from the word you meant. Text in the wrong language is caught before a card is made. See Typos and language mismatches.
The translation
Every new translation is checked a second time, in a separate step, while the card's details are generated. That step looks at the translation in its full context and decides whether it's correct.
If the translation is wrong, flangu replaces it with the correct one before the card is finished, and the details are generated for the corrected translation. A short notice, Translation corrected, shows what changed.
If a better translation can't be confirmed right away, the card is still created, and a notice reads This translation may be wrong. The entry moves to the front of the queue for the next check. If it turns out to be wrong, your card is corrected automatically. You can also tap Undo to remove the card.
The card's details
Synonyms, definitions, examples, alternatives, and pronunciations follow strict rules. A few of them:
- Words and sentences must be natural: what a native speaker would actually say.
- An established word, or a loanword that native speakers really use, is always chosen over an invented one.
- Example sentences are written as pairs. Each one shows the word where it's the natural choice, instead of forcing it into a sentence where a native speaker would use another word.
- Every field describes the same meaning as the card's translation.
Before any content is saved or shared with other users, it passes automatic validation. Content in the wrong script or language is removed. Content with the wrong structure or length is held back and not shown. A missing field is better than a wrong one, so flangu leaves a field out rather than guessing.
Regular checks
Translations and their details are stored once and shared by all flangu users (see The shared translation cache). This means a single check improves the card for everyone who learns that word.
Shared entries are reviewed again on a regular schedule by an independent checker. Each check goes through every field: the translation, part of speech, synonyms, definitions, examples, alternatives, and pronunciation. Entries are checked in this order of priority:
- Entries that a user reported.
- Entries flagged as uncertain when they were created.
- Entries that are used often.
When a check finds a problem, it's fixed automatically:
- A wrong translation is replaced with the correct one, and new details are generated for it.
- Inaccurate details are rewritten.
Every fix is checked again before it's used. Only a fix that passes this second check reaches new cards or your saved cards. An entry that can't be fixed automatically goes to the flangu team for review.
Card corrections
Each card keeps its own copy of its content. When a regular check fixes a shared entry, flangu sends the fix to every saved card made from it. This is a card correction.
A correction changes only the content that was wrong. It never changes:
- the text you translated from;
- your review history, schedule, or progress;
- cards you've edited yourself. Your own changes always win. See Editing a flashcard.
Each correction says why the card changed, for example: "The translation was wrong. It was replaced with a more accurate one." You can compare the old and new version side by side.
Choosing how corrections apply
Go to Settings → General → Card corrections and choose a mode:
| Mode | What happens |
|---|---|
| Update automatically (default) | Fixes apply right away. A short notice tells you how many cards were corrected. Tap View to see them and undo any change. |
| Ask me first | Fixes wait until you review them. A banner on Home and on the deck screen shows how many are waiting. Update each card or keep it as it is. |
Corrections are never applied in the middle of a review session. If a card you're reviewing has a correction waiting, a Correction waiting row appears above it.
History
Settings → General → Card corrections also lists past corrections. Open one to see the change, restore the previous version, or apply a correction you kept.
Corrections reach your cards when the app syncs. On a device that's offline, they arrive with the next sync.
Testing every change
Every change to how flangu generates or checks content is tested before it reaches you. Each change is measured against collections of difficult, hand-checked test cases in many languages, and compared with the version you use now. The results are also compared side by side by people who don't know which version produced which answer.
A change is released only when it makes content more accurate.
If you spot a mistake
Mistakes are rare, but if something on a card looks wrong, report it with the feedback icon on the 
Translator screen. See Reporting incorrect metadata.
A report moves the entry to the front of the queue for the next check. If it's fixed, your card receives a correction that starts with "You reported this card. Thanks!". Every report also improves the entry for all other users.