Counting in Irish is the point where learners discover that the language is not going to behave. There is not one set of numerals but three, and choosing between them depends on whether you are counting nothing in particular, counting things, or counting people.
Set one: counting aloud
| Number | Irish | Sounds roughly like |
|---|---|---|
| 1 | a haon | a hayn |
| 2 | a dó | a doe |
| 3 | a trí | a tree |
| 4 | a ceathair | a KAH-hir |
| 5 | a cúig | a KOO-ig |
| 6 | a sé | a shay |
| 7 | a seacht | a shokht |
| 8 | a hocht | a hukht |
| 9 | a naoi | a nee |
| 10 | a deich | a deh |
The a in front is part of the form when counting in the abstract — reciting, giving a phone number, stating a figure. Drop it and you have the form used with nouns, which is the second set.
Set two: counting things
| Irish | English | What happened |
|---|---|---|
| aon bhád | one boat | lenition: bád → bhád |
| dhá bhád | two boats | lenition |
| trí bhád | three boats | lenition |
| ceithre bhád | four boats | lenition |
| cúig bhád | five boats | lenition |
| sé bhád | six boats | lenition |
| seacht mbád | seven boats | eclipsis: bád → mbád |
| ocht mbád | eight boats | eclipsis |
| naoi mbád | nine boats | eclipsis |
| deich mbád | ten boats | eclipsis |
Two things to notice. The noun stays singular — trí bhád is "three boat", not "three boats" — and the number changes the start of the word after it. Lenition for two through six, eclipsis for seven through ten, every time.
Lenition adds an h; eclipsis adds a letter that replaces the sound. Bád becomes bhád (pronounced with a w or v sound) under lenition, and mbád (pronounced "mawd") under eclipsis — the written b goes silent. This is why an Irish dictionary lookup fails for beginners: you have to strip the mutation before you can find the word.
Set three: counting people
| Irish | English |
|---|---|
| duine amháin | one person |
| beirt | two people |
| triúr | three people |
| ceathrar | four people |
| cúigear | five people |
| seisear | six people |
| seachtar | seven people |
| ochtar | eight people |
| naonúr | nine people |
| deichniúr | ten people |
These are whole separate words, not the numbers plus a noun. Beirt means "two people" by itself, and it takes a lenited noun after it: beirt mhac, two sons. Irish families are counted this way in ordinary speech, so the set comes up constantly and cannot be avoided by using the object numbers instead.
What to learn in what order
Take the counting set first and use it for everything a figure appears in — times, prices, phone numbers. Add the object set with a single noun you know well, so the mutation pattern is attached to a real word rather than to a rule. Leave the personal numerals until those two are solid; they are short, irregular and easier to memorise once the first two are not competing for attention.
Look up Irish words offline
The free English-Irish Dictionary gives meanings and word forms without needing a connection.
Open the dictionary appFrequently asked questions
Why does Irish have three sets of numbers?
Because they do different jobs. One set is for counting in the abstract, one for counting objects, and one — the personal numerals — exists only for counting people. Most languages manage with one; Irish kept all three, and they are not interchangeable.
Which set should a beginner learn first?
The counting set with a haon, a dó, a trí. It handles phone numbers, prices, dates and saying a figure aloud, which is most of what a learner needs early. The object and personal sets come next.
What do the numbers do to the following word?
They trigger mutations. Two, three, four, five and six lenite — an t-séimhiú, written as an added h. Seven, eight, nine and ten eclipse. This is not optional decoration; the mutation is part of the number's grammar.