FlashFluency vs Onymera
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
FlashFluency
Master Korean from basic Hangul to fluency with AI-powered pronunciation feedback and sentence building. Learn one new concept at a time with spaced repetition for effective memorization. Instant explanations for vocabulary and grammar are available.
- Syllable-level AI pronunciation feedback
- AI sentence coach for writing practice
- +1 system for learning one concept at a time
- Spaced repetition for memorization
- Instant vocabulary and grammar explanations
- Frictionless learning experience
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Flash Fluency is an all-in-one Korean app, from Hangul to fluency. So is every other app. Here's what's different. CONTENT-TO-CURRICULUM Song lyrics, a news article, your class notes, a drama script. Bring any Korean you actually care about and Flash Fluency pulls out every vocab word and grammar point, then teaches them to you in new sentences. SYLLABLE-LEVEL PRONUNCIATION FEEDBACK AI feedback on every syllable you speak, covering every Korean pronunciation rule. Your recording beside a native voice, block by block, so you know exactly what you got wrong and how to fix it. TRANSLATION COACHING Write real Korean from your first lesson. Every sentence comes back with corrections, naturalness tips, and style notes, down to the particle. +1 AND SRS Each sentence introduces exactly one new concept, so you're never lost. Spaced repetition brings it back right before you'd forget it. SKILLS THAT STACK Read it, hear it, recall it, translate it, speak it. Each stage feeds the next. Complete beginner? Start with the Hangul course, then Korean Fundamentals. No prior Korean needed. Coming soon: conversational exercises and a 10,000-word TOPIK learning order. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://www.flashfluency.net/privacy_policy
Onymera
Learn new words daily with this app that displays a different word on your lock screen every minute. It offers extensive vocabulary lists in nine languages, complete with definitions, example sentences, and pronunciation guides. The app works offline and allows for personalized word selection based on your needs.
- Daily word display on lock screen
- Extensive vocabulary in 9 languages
- Definitions, example sentences, and pronunciation
- Offline functionality
- Customizable word selection
- Word history and saved words
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A new word, where you already look. Onymera puts a word on your lock screen and changes it about once a minute, so you meet a different one almost every time you glance at your phone. Not a notification. Not a feed. Nothing to open, nothing to remember, no streak to keep alive. NINE LANGUAGES, 32,000 WORDS AND COUNTING, ALL FREE • Korean - 5,965 words: the complete National Institute of Korean Language learner list, beginner through advanced, with Hanja origins where they help. • Japanese - 3,984 words: JLPT N5 and N4, and N3 well under way. Every entry carries its kana reading and romaji. • Chinese - 4,571 words: HSK 1 to 5, and the start of HSK 6, with pinyin. Simplified characters. • English - 4,295 words across four tiers, from everyday to genuinely rare. • Spanish - 2,709 words: CEFR A1, A2 and B1, with IPA so you know where the stress falls. • Portuguese - 2,592 words: A1, A2 and B1. Brazilian: ônibus, trem, celular, você. • French - 2,708 words: CEFR A1, A2 and B1, with IPA for everything the spelling hides. • German - 2,699 words: CEFR A1, A2 and B1, from the Goethe-Institut's own examination lists. • Italian - 2,697 words: CEFR A1, A2 and B1, with open and closed vowels marked. The word lists follow the official curriculum for each language where one exists, and every entry passes the same validator before it ships. Pick a language and the whole rotation follows; your history and saved words are kept separately for each one. EVERY ENTRY HAS A SENTENCE A definition in plain English, under 140 characters. An example sentence where the meaning is obvious from context, with a translation. Tap the widget for the pronunciation, the definition and the sentence, with the last five words you were shown underneath, so a word you half caught is never lost. TELL IT WHAT YOU'RE HEADING INTO Say, in plain English, what words you want to see: "a week in Seoul", "my first job in a Berlin office", "nothing beginner" - and the rotation follows. Thousands of words per language means even a very specific request comes back with a real list. This is the one optional purchase; everything else is free and complete without it. DOWNLOADS ONCE, THEN WORKS WITH NO SIGNAL A language is fetched the first time you pick it - a few hundred kilobytes - and from then on it lives on your phone. No account, no sign-up, nothing to fetch on a plane. The lists keep growing, and each language updates itself the next time you use it: new words arrive without an app update. A LIBRARY THAT FILLS ITSELF Your history is rebuilt from the rotation itself, so it is complete whether or not you opened the app. Save the ones you want to keep. Search by the word, by how it sounds, or by what it means in English. Accents and umlauts are optional: "manana" finds mañana, "schon" finds schön. LOCK SCREEN AND HOME SCREEN A rectangular and an inline widget for the lock screen. Small and medium widgets for the home screen: the small one is a glance, the medium one brings the example sentence with it. All free, and the app shows you how to add them the first time you open it. OPTIONAL: PERSONALIZATION - $2.99, ONCE The steering described above, plus the pace: slow the widget down to one word an hour, or one a day to sit with, rather than a new one every look. Your selection follows you to any device you sign in on. One payment. No subscription, ever. Nothing recurring anywhere in the app. — iPhone, iOS 17 or later. Privacy: onymera.app/privacy
Screenshots
Verdict
The clearest difference is update cadence: Onymera at every 2 days against FlashFluency's every 3 weeks. FlashFluency's advantage is device support (3 vs 1) and iOS requirement (13.0 vs 17.0). On price, rating, review sentiment and ratings volume there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. FlashFluency sells 2 in-app purchases, starting at $5.99 per month and Onymera sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
On the App Store both sit at effectively the same score — 5.0 for FlashFluency against 5.0 for Onymera. Both are backed by a comparable volume of ratings — 2 and 3 respectively. Written reviews split almost evenly too, at 100% and 100% positive.
FlashFluency ships an update every 3 weeks, Onymera every 2 days. The most recent releases landed on October 6, 2026 and October 9, 2026 respectively.
| Parameter | FlashFluency | Onymera |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (2 ratings) | 5.0 (3 ratings) |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| Number of ratings | 2 | 3 — better |
| Update frequency | Every 3 weeks | Every 2 days — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 13.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 94 MB | 2 MB |
| Age rating | 12+ | 4+ |
| Developer | Flash Fluency | Convoya |
Customer experience
FlashFluency
Onymera
In-app purchases
FlashFluency
- Flash Fluency Core7 Days trial$5.991 Month
- Flash Fluency Premium7 Days trial$12.991 Month
Onymera
- Onymera Full Unlock$2.99









