flangu is a vocabulary-learning app for mobile. You build flashcards from words you want to learn, and the app decides when to show each card again so you remember it long-term.
The core idea is simple: each card has a front and a back. During a review session you see the front, try to recall the back, then reveal it and rate how well you knew it. flangu uses your rating to schedule the next review. Cards you know well come back after weeks or months, while cards you struggle with come back the next day.
Cards and decks
A card is a single question-and-answer pair. The front is typically a word in one language; the back is its translation, plus optional extras like a definition, example sentences, and pronunciation audio.
A deck is a collection of cards grouped around a topic or language, such as "French Idioms" or "Business English". Every card belongs to a deck.
Creating your first card
Open the card creation screen by tapping 
in the bottom navigation bar.
You can create cards in two modes:
Manual: you type both the front and the back yourself.
Translation: you type one side and flangu translates it automatically.
Before you can save a card, you need a deck to put it in. Tap 
Decks at the top of the screen and create or select one.
Next, set the language for each side of the card by tapping the flag icon in the top-left corner of each card panel.
Translation mode
- Tap the front card panel and type the word you want to learn.
- Tap Translate.
- After a moment, the translated text appears in the back panel and a "Flashcard created" message confirms the card is saved.
Shortly after, linguistic metadata (synonyms, definitions, example sentences, and images) is added to the card automatically.
Manual mode
- Tap the front card panel and type the word.
- Tap the back card panel and type the translation.
The card is saved immediately. No translation step is needed.
Note
In Translation mode, the card is created as soon as you tap Translate. You do not need to do anything else. The linguistic metadata appears a few seconds later in the background.
Your first review session
Cards are only shown for review when the app determines it is the right time. A 
Study button appears on a deck whenever cards are due.
You can find it in the 
Home tab, the Decks tab, or on the individual deck screen. If the button is not visible, there are no cards due for that deck right now.
Tap Study to begin.
How a review works
- The front of a card is displayed. Take a moment to recall the answer.
- Tap the lower half of the screen (
) to reveal the back. - Rate how well you knew it using one of the four buttons:
| Button | When to use it |
|---|---|
| Again | You did not know the answer. Use this, and only this, for a failure. |
| Hard | You knew the answer, but it took significant effort. |
| Good | You knew the answer with normal effort. |
| Easy | The answer came immediately with no effort. |
Warning
Do not tap Hard if you did not know the answer. Again is the correct rating for any card you could not recall. Using the wrong rating will cause the card to be scheduled as if you know it, so it will not return soon enough to reinforce the memory.
After you rate a card, the next one appears automatically. When all due cards have been reviewed, the session ends.
That's everything you need to get started. Create a few cards, wait until they are due, and complete your first review.