Geirfa offers two complementary ways to learn Welsh vocabulary: reference tools for exploring how the language works, and practice games for making words stick.
The home screen shows all available modes, divided into reference tools and practice games. Use the tier and category dropdowns at the top to filter the vocabulary pool before starting any game. The word count updates to show how many words match your current filters.
The Ymadrodd y Dydd (Phrase of the Day) card appears at the top — a different idiom or phrase each day. Use the arrow buttons to browse the history, or the refresh button for a random phrase.
The Quick Lookup box allows instant Welsh↔English search at any time. Tap any result to see its full details, or add it to your revision list.
The shortcut bar below the lookup gives one-tap access to every mode.
The reference tools explore the structure of Welsh rather than testing recall. They are best used to deepen understanding before or alongside the practice games.
Welsh is a highly morphological language — most words are built from a smaller set of roots. The Gwreiddiau section groups words into 143 root cards, each showing the full family: nouns, verbs, adjectives, and related shadow words.
Tap any chip in the chip bar to open that root card. The number badge on each chip shows how many entries the card contains. Use the sort dropdown to order chips alphabetically, by most entries, or by fewest entries.
Each card has a coloured header showing the root word and its English meaning. Entries are grouped by type: Enwau (nouns), Ansoddeiriau (adjectives), Berfau (verbs), and Cysgodion (shadow words — related concepts from different roots). Each entry includes a breakdown note explaining how it was formed.
Each root card has a 🖨 print button in the header. Tap it to open a print view with a colour/B&W toggle. The print view is formatted for A4 and includes all entries on the card.
Many cards include notes on etymology — where the root came from and how it relates to other languages. These explain patterns like vowel alternations (e.g. gweld → golwg), mutation effects on stems, and historical connections to Latin, Old Welsh, or English.
The Morffoleg section covers the 15 most productive Welsh prefixes and suffixes. Understanding one suffix can unlock dozens of new words — once you know that -adwy means "capable of being done", you can decode gweladwy (visible), cofiadwy (memorable), and credadwy (believable) instantly.
Prefix cards include: an- (negation, triggers aspirate mutation), di- (without/removing, triggers soft mutation), ym- (reflexive, from Latin ambi-), ad- (re-/back), and more.
Suffix cards include: -adwy (capable of — Welsh -able/-ible), -aeth and -iaeth (abstract noun), -ol (adjective — relating to), -ydd (agent/doer), -gar (inclined to), -og (full of), -us (having), -fa (place), and more.
Each card includes 20 example words with breakdowns, pattern notes, and a note on any semantic drift — for example, ofnadwy originally meant "capable of causing fear" but has shifted to simply mean "awful".
The same 🖨 print button is available on each morphology card, with the same colour/B&W toggle.
Adeiladu (to build) takes 95 carefully chosen Welsh words and deconstructs them into their morphological components — prefix, stem, and suffix — with full explanations of each part.
The Adeiladu home screen shows a randomly selected word in large gold text with its English meaning. Below the word, coloured dots hint at the structure without revealing it:
Think about how the word might be built, then tap the reveal button to see the full pill breakdown.
After revealing, the word's components appear as coloured pills:
Where a stem has been mutated, the canonical (unmutated) form is shown below the pill. Tap any pill to open a warm cream popover explaining what that morpheme does, its etymology, and three example words that share the same morpheme.
Use ← Nôl and Nesaf → to move through the shuffled word pool, or tap ↺ to jump to a random word. The position indicator (e.g. "3 / 20 · trefn ar hap") shows where you are in the shuffled sequence.
Use the Rhagddodiad (prefix) and Ôl-ddodiad (suffix) dropdowns to filter the word pool. For example, selecting an- shows only words built with that prefix. The pool reshuffles automatically when filters change.
Tap Gweld y rhestr / Browse all to see all words as a list with mini pills showing their structure. Tap any word to open its reveal screen.
Trefnolion covers ordinal numbers, dates, and times through both reference tables and four interactive practice modes.
The reference tab has collapsible sections covering: ordinal numbers 1af–31ain (with masculine and feminine forms), months, days of the week, and times. Each section can be opened and closed independently.
Each of the four tabs (Trefnolion, Dyddiadau, Amser, Enwau) offers two practice modes:
Dewis — multiple choice. The Welsh form is shown; choose the correct English equivalent (or vice versa) from four options. Correct answers auto-advance after a short pause.
Teipio — type-in. Type the Welsh form from an English prompt. The check button (or Enter) submits your answer.
All practice modes share the same navigation: ← Nôl to go back, Nesaf → to advance, and Hepgor to skip a question. The progress bar and score pill update throughout. After answering incorrectly, the correct answer is shown in the feedback bar before advancing.
After completing a set, the results screen shows your percentage, and a breakdown of correct, incorrect, and skipped answers. Tap Dim ond anghywir to retry only the questions you got wrong or skipped.
The Idiomau section provides a browsable reference of 329 Welsh idioms, each with:
Idioms are numbered #001–#329. They span all categories from everyday expressions to proverbs and cultural sayings.
The practice games build active vocabulary through varied recall modes. All games draw from the vocabulary pool set by the current tier and category filters on the home screen.
Flashcards are the foundation of the app — the place to start and the mode to return to most often. Each card shows either the Welsh word or its English meaning (depending on direction), and you tap to reveal the other side.
Use the Cy → En and En → Cy buttons to set direction. Welsh-to-English builds recognition; English-to-Welsh builds production. Production is harder but more valuable — it's what you need when speaking.
Nouns are colour-coded by grammatical gender: blue for masculine (gwrywaidd), pink for feminine (benywaidd). Pronouns and some other words have their own colour. This colour coding is consistent across all game modes.
Tap the star ★ on any flashcard to add the word to your session revision list. You can then run a focused session on just those words using the revision list button on the home screen. The list clears when you close the session.
Multiple choice presents four options — the target word plus three smart distractors drawn from the same category or with similar sounds. Select the correct translation.
After answering, the correct option turns green and incorrect options are shown. The game auto-advances after a brief pause on a correct answer, or waits for you to continue after a wrong answer so you can see what the correct answer was.
Available in both Welsh→English and English→Welsh directions.
Teipio is the most demanding mode — you must spell the Welsh word correctly from an English prompt (or vice versa). This builds production rather than recognition.
Accent matching is lenient: if you type cofiadwy without the circumflex, it will still be accepted. However, practising the correct spelling (including mutations) is good habit.
Press Enter or tap the check button to submit your answer. The correct answer is shown if you get it wrong.
Match Welsh words to their English meanings in the fastest time possible. Five pairs per round, five rounds. Tap a Welsh word, then its English meaning to pair them. Correctly matched pairs clear from the board.
Paru is the challenge mode — it tests speed as well as accuracy. Good for warm-up sessions.
Match words to their opposites from a pool of 450+ curated antonym pairs. This mode draws from the full antonym database regardless of tier or category filters — it is vocabulary-independent and always available.
Antonyms span adjectives (hapus/trist), verbs (agor/cau), and nouns (dechrau/diwedd). Working through antonyms builds a richer understanding of how words relate than translation alone.
Welsh has three consonant mutations — meddal (soft), trwynol (nasal), and llaes (aspirate) — that change the initial consonant of words in certain grammatical contexts. Treigladau has three practice modes:
Adnabod — identify which mutation has been applied in a given sentence.
Llenwi — fill in the correct mutated form in a gap.
Teipio — type the mutated form in a sentence context.
Welsh plurals are formed by many different rules — add -au, add -ion, remove -en, change internal vowels, or use entirely irregular forms. The Lluosog mode presents 800+ singular-plural pairs and tests your knowledge of both directions.
Welsh homophones — words that sound identical but have different meanings and spellings. Examples: gwn (gun / I know), mwg (mug / smoke), ton (wave / tune). A matching game that sharpens both listening comprehension and spelling.
Welsh negation is more varied than English. The Negyddion mode covers the main patterns: ddim yn (the most common), nid (formal/literary), peidio (don't!), and others. Reference tables and a practice mode.
Vocabulary is organised into five tiers by frequency and difficulty:
| Tier | Description | Words |
|---|---|---|
| 1 | Core everyday vocabulary — most frequent and essential | ~200 |
| 2 | Common vocabulary — high frequency in everyday speech | ~300 |
| 3 | Useful vocabulary — encountered regularly | ~1,000 |
| 4 | Extended vocabulary — useful for fluency | ~2,000 |
| 5 | Advanced vocabulary — specialised or literary | ~3,500+ |
The tier dropdown filters cumulatively — Tier 1–3 includes all words from Tiers 1, 2, and 3. The word count on the home screen updates to show the active pool size.
Filter by semantic category — body, emotions, nature, work, language, food, travel, and many more. Combine with tier filters to focus on exactly the vocabulary you need for a specific context.
Filter by grammatical category: nouns, verbs, adjectives, adverbs, phrases, and idioms.
1. Cardiau Flash, Tier 1–2 — Start here. Ten minutes daily on the core 500 words. Build recognition before production.
2. Dewis — Move to multiple choice once words start to feel familiar. Distractors make you think about meaning more carefully.
3. Gwreiddiau — Browse a few root cards. Seeing a root family at once (e.g. all the gwybod derivatives) multiplies your vocabulary rapidly.
4. Adeiladu — Understand how words are built. The dot teaser and pill reveal build morphological awareness that accelerates learning.
5. Teipio — Spelling practice consolidates words. Once you can type a word correctly, it tends to stay.
Ten minutes of focused practice beats one long session. A good short session: 5 minutes of Cardiau Flash at your current tier, then 5 minutes of Dewis or Teipio. Add Gwrthebau or Adeiladu when you want variety.
Use the revision list (★ star) to flag words that keep tripping you up. Return to the revision list at the start of each session before moving to new vocabulary.