Cardiau Cymraeg is a Welsh vocabulary flashcard app for iPhone, bilingual from the very start. Search finds a word from its mutated forms, and each word comes back as it starts to fade.
Coming to the App Store
See what it doesThe app shows you a Welsh word. Tap the card to see what it means, then say how well you knew it. The app works out when to show you that word again.
Every label, button, and message in the interface is written in both languages, and neither is a fallback for the other. On first launch the app follows your phone’s language, and after that it remembers the one you choose in the app.
Welsh words change their first letter after certain words. Type gath, nghath, or chath and search finds cath, a cat. Accents are optional, so dwr finds dŵr.
The 1,000 words come in order of how often they’re used in contemporary Welsh, from Cardiff University’s Yr Amliadur frequency lists. Up to 20 new words a day, the most common first.
Answer Hard, Good, or Easy. Each answer shows when the word will come back, and FSRS, an open scheduling method, sets that time from how well you know the word.
Most of the 1,000 words come with a recording you can play. Most recordings use AI voices, and each one was chosen by ear, word by word.
Cardiau Cymraeg is built to work as well in Welsh as in English, down to the details a Welsh speaker notices when they’re missing.
All of the interface text exists in Welsh and in English, and the app switches between them as soon as you choose, without restarting.
After a number, a Welsh noun can change its first letter. So the answer times read 2 ddiwrnod, 2 fis, and 1 flwyddyn, worked out from Welsh rules rather than an English plural.
The language switch shows each language’s name in that language, so you can find either one from the other. Welsh words are tagged as Welsh in the app’s text.
| English | Cymraeg |
|---|---|
| Show answer | Dangos yr ateb |
| How well did you know it? | Pa mor dda oeddech chi’n ei wybod? |
| Hard · Good · Easy | Anodd · Da · Hawdd |
| 2 days | 2 ddiwrnod |
| That’s everything for today | Dyna’r cyfan am heddiw |
| New cards and reviews will be ready tomorrow. | Bydd cardiau newydd ac adolygiadau ar gael yfory. |
The Welsh on this page and in the app is translated with Claude, an AI model, and checked by Rob Nash, Async Digital’s director, who is learning Welsh.
Building a service that has to work in Welsh? Async Digital builds apps like this one. Read what the Welsh Language Standards ask of apps and websites, or get in touch.
The word list is built from the open sources below.
Frequency lists for contemporary Welsh. Knight, D., Morris, S., Tovey-Walsh, B., Fitzpatrick, T. and Anthony, L. (2020). Cardiff University.
doi.org/10.17035/d.2020.0120164107 CC BY-SA 4.0The English Wiktionary’s Welsh entries, by way of the extract kaikki.org made with Tatu Ylonen’s wiktextract, published on 21 October 2026. Meanings were shortened, and some were rewritten by hand.
en.wiktionary.org kaikki.org/dictionary/Welsh CC BY-SA 4.0Uned Technolegau Iaith, Prifysgol Bangor.
doi.org/10.5281/zenodo.5211667 CC0 1.0Cardiau Cymraeg is not on the App Store yet. This page will link to it once it is.
Cardiau Cymraeg
Coming to the App Store
Requires iOS 26 or later. In Welsh and English.
The app collects no personal data. There is no account and no analytics, and your progress stays on your iPhone.
How the app handles data: privacy policy.