Kotoba is an offline flashcard app for building Japanese vocabulary. No account, no server, no tracking — the 651 words and your progress stay on your device.
WHAT IS IN IT
Nine decks built from real dictionary records, not made-up lists:
• Everyday basics — 128 words for people, time, places and the adjectives around them
• Food and drink — 82 words for meals, ingredients and ordering
• Travel — 83 words for stations, hotels, shopping and directions
• Doctor and medicine — 70 words for clinics, symptoms and prescriptions
• Disaster and safety — 60 words for earthquakes, typhoons, evacuation and crime
• Housing and neighbours — 58 words for contracts, utilities and rubbish rules
• Office and bank — 58 words for paperwork, insurance, the post and your account
• Daily commute — 58 words for trains, buses, transfers and bike parking
• Neighbours and work — 54 words for greetings, local events and colleagues
Eight of those nine follow the Japanese Agency for Cultural Affairs' 「生活Can do」list: the everyday situations a newly arrived resident has to handle, graded A1 to B2. The level shown on a deck is the span of that list's can-do statements for the situations behind it. It is not a JLPT claim, and no sentence from the list is copied into the app.
Every card shows the written form, the kana reading, the romaji and the meaning, plus the part of speech. The kanji, kana, meaning and part of speech are read from JMdict, the open Japanese dictionary, and each card carries the dictionary record it came from.
HOW THE REVIEWS WORK
Tap a card to flip it, then rate what happened: Again, Hard, Good or Easy. Each button shows the next interval before you press it, because that number is the real schedule result, not a guess.
• Again brings the card back in ten minutes — and also later in the same session, so a difficult word does not wait a full day to return.
• Hard grows the interval slowly, by 20 %.
• Good follows the classic 1 day, then 6 days, then interval × ease ladder.
• Easy stretches that by 30 %.
Answering a card wrongly lowers its ease factor, which is what makes genuinely hard words come back sooner. A lucky streak cannot hide a word you keep missing.
DAILY GOAL AND STREAK
Pick from six targets — 5, 10, 15, 20, 30 or 50 reviews a day — and 0, 5, 10, 15, 20 or 30 new cards a day. A ring on the Today screen fills as you go. The streak survives until your local midnight, so a busy morning does not delete a week of work just because today is not finished yet.
SEE WHAT YOU ACTUALLY KNOW
The Progress tab groups your words by the interval the schedule has reached: New, Learning, Familiar (7 days or more) and Mastered (21 days or more). The numbers come from your own review history — total reviews, current and longest streak, words studied, average interval, the last 14 days, and a breakdown per deck. Before you have studied anything, the averages are shown as empty rather than invented.
PRONUNCIATION
Tap the speaker on a card to hear the reading. The voice is the one already installed on your device; if there is no Japanese voice, the button does not appear and the card works as usual.
DETAILS WORTH KNOWING
• Works on a plane: the app makes no network request at all.
• Your progress is one small file on the device. Resetting it is one button in Settings, with a confirmation first.
• Light-only interface, with the word itself set at 56 pt on the card.
• Text colours measure at least 4.6:1 against both backgrounds the app uses — past WCAG AA for body text.
• Vocabulary source: JMdict, licensed CC BY-SA 4.0, cited inside the app.
• The meanings are JMdict's English definitions, so the gloss on each card stays in English whatever language the app is set to.
Start with the deck that matches what you need this week, set a target you can hit tomorrow, and let the schedule decide when each word comes back.
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