1 to 19

Irish has several different ways of using numbers depending on the context. You will use one form for abstract counting (“one, two, three…”), another for counting nouns (“one boat, two boats”), a special set for counting people, and another for ordinal numbers (“first, second, third”). This guide covers all four systems for the numbers 1 to 19.

Abstract Counting (Maolúimhreacha)

When you are counting aloud without referring to any specific objects, you use the abstract numbers, or maolúimhreacha. These are usually preceded by the particle a.

• 1: a haon
• 2: a dó
• 3: a trí
• 4: a ceathair
• 5: a cúig
• 6: a sé
• 7: a seacht
• 8: a hocht
• 9: a naoi
• 10: a deich
• 11: a haon déag
• 12: a dó dhéag
• 13: a trí déag
• 14: a ceathair déag
• 15: a cúig déag
• 16: a sé déag
• 17: a seacht déag
• 18: a hocht déag
• 19: a naoi déag

Counting Nouns (Bunuimhreacha)

When counting objects or things, you use the cardinal numbers, or bunuimhreacha. These numbers often cause a mutation (lenition or eclipsis) on the noun that follows, and the noun itself remains in the singular form.

Numbers 1 and 2

The number one, aon, lenites the noun that follows. It is often used with amháin (“only” or “one”) for clarity. The number two, dhá, also lenites the noun.

• aon bhád amháin - one boat
• dhá bhád - two boats

You can also express “one” by placing amháin after the noun.

• bád amháin - one boat

Numbers 3 to 6

The numbers from three to six all cause lenition on the following noun.

• trí bhád - three boats
• ceithre bhád - four boats
• cúig bhád - five boats
• sé bhád - six boats

Numbers 7 to 10

The numbers from seven to ten all cause eclipsis on the following noun.

• seacht mbád - seven boats
• ocht mbád - eight boats
• naoi mbád - nine boats
• deich mbád - ten boats

Numbers 11 to 19

To count nouns from 11 to 19, you place the noun between the unit number (1-9) and the word déag. The mutation on the noun is determined by the unit number.

• aon bhád déag - eleven boats (from aon + lenition)
• dhá bhád déag - twelve boats (from dhá + lenition)
• sé bhád déag - sixteen boats (from sé + lenition)
• seacht mbád déag - seventeen boats (from seacht + eclipsis)

Counting People (Uimhreacha Pearsanta)

Irish uses a special set of collective nouns for counting people from 2 to 12. For other numbers, the standard cardinal numbers are used, but with a slightly different mutation pattern for 13-19.

Numbers 1 to 12

For one person, you use the standard cardinal number. From 2 to 12, special forms are used. The noun following these forms is in the singular.

Numbers 13 to 19

From 13 to 19, you use the standard cardinal numbers with the noun followed by déag. However, the mutation pattern is different from counting objects: numbers 13-16 cause lenition, while 17-19 cause eclipsis.

• trí fhear déag - thirteen men (lenition)
• sé fhear déag - sixteen men (lenition)
• seacht bhfear déag - seventeen men (eclipsis of f is bhf)
• naoi bhfear déag - nineteen men (eclipsis of f is bhf)

Ordinal Numbers (Orduimhreacha)

Ordinal numbers (“first”, “second”, “third”, etc.) are used to indicate position in a sequence. They are usually preceded by the definite article an.

Zero

The number zero is usually náid. It can also be referred to as neamhní.