Grammar Reference

Current level: Beginner — Phase 2 rules unlock after you level up in Practice.

Irish is a VSO language — sentences go Verb, then Subject, then Object. This is the opposite of English word order and is one of the most important things to internalise early. Everything else builds on this foundation.

All examples use words from the vocabulary list. Grammar explanations follow An Caighdeán Oifigiúil (the Official Standard Irish).

Phase 1

Tá — the verb 'to be' (present tense)

Irish word order is Verb–Subject–Object (VSO) — the verb always comes first. Tá is the present tense of bí (to be). It expresses states, existence, and — combined with a prepositional pronoun — replaces the English verb 'to have'.

Tá an cat mór. The cat is big. Verb first: Tá → an cat → mór

Tá leabhar agam. I have a book. Literally: "Is a-book at-me"

Tá fear ann. There is a man there. 'Ann' means 'there / in it'

Phase 1

Possession: 'agam' — I have

There is no verb 'to have' in Irish. Instead, possession uses Tá X agam — literally X is at me. Agam is the prepositional pronoun formed from ag (at) + mé (me). All persons follow the same pattern:

Form	Meaning	Example
agam	at me	Tá cat agam — I have a cat
agat	at you	Tá carr agat — You have a car
aige	at him	Tá madra aige — He has a dog
aici	at her	Tá leabhar aici — She has a book
againn	at us	Tá teach againn — We have a house
agaibh	at you (pl.)	Tá bia agaibh — You have food
acu	at them	Tá carr acu — They have a car

Phase 1

Indefinite nouns — no article

Irish has no indefinite article — leabhar means both 'book' and 'a book'. Indefinite nouns carry no mutation. They appear exactly as listed in the dictionary. This means the absence of the article 'an' is itself meaningful.

Tá leabhar agam. I have a book. No 'a' in Irish — just the bare noun

Tá uisce ann. There is water there. No 't-' prefix without the article

Phase 1

Existential sentences: 'ann'

Ann (there / in it) is used to express that something exists or is present. Tá X ann = There is an X there. It is one of the most common sentence patterns in Irish and does not cause any mutation on the noun.

Tá cat ann. There is a cat there.

Tá bia ann. There is food there.

Tá teach ann. There is a house there.

Phase 1

Definite article: masculine nouns

The definite article is an. For masculine nouns in the nominative case (subject of the sentence), an causes no mutation. The noun stays exactly as in the dictionary. This is one way masculine nouns are simpler than feminine ones.

an leabhar the book No change to 'leabhar'

an fear the man No change to 'fear'

an bord the table No change to 'bord'

an carr the car No change to 'carr'

Phase 1

Special rule: masculine vowel-initial nouns → 'an t-'

Masculine nouns that begin with a vowel (a, e, i, o, u) take an t- (with a hyphen) instead of plain an. This is unique to masculine nouns — feminine vowel-initial nouns just take an with no addition.

an t-uisce the water Masculine — gets t- prefix

an oíche the night Feminine — no t- prefix!

The hyphen in an t-uisce is always written. Don't omit it.

Phase 1

Predicative adjectives with Tá

When an adjective follows Tá as a predicate — describing what the subject is like — it does not mutate, regardless of the noun's gender. This is called a predicative adjective. Compare this with attributive adjectives (placed directly after a noun in a noun phrase), which do agree with gender — but that's a Phase 3 topic.

Tá an bord mór. The table is big. 'Mór' doesn't mutate

Tá an cat beag. The cat is small. 'Beag' doesn't mutate

Tá an bhean óg. The woman is young. 'Óg' doesn't mutate — but 'bean' is lenited as a feminine noun

Phase 2

Definite article: feminine nouns and lenition (séimhiú)

Feminine nouns are lenited after an in the nominative case. Lenition (séimhiú) inserts h after the initial consonant. There are 9 lenitable consonants. The 't', 'd', 's' lenitions produce sounds quite different from the originals.

Original	Lenited	Example
b	bh	bean → an bhean (the woman)
c	ch	clann → an chlann (the family)
d	dh	doras → an doras → an dhoras*
f	fh	fuinneog → an fhuinneog (the window)
g	gh	gaoth → an ghaoth (the wind)
m	mh	máthair → an mháthair (the mother)
p	ph	péist → an phéist (the worm/beast)
s	sh	sráid → an tsráid* (the street)
t	th	tonn → an tonn → an thonn*

* fh is silent. sh and th are also approximately silent (produce a soft 'h' sound). Note: consonant clusters sc, st, sp are not lenited — so an scoil (not an scoil with séimhiú).

an bhean the woman bean → bhean (b → bh)

an chlann the family clann → chlann (c → ch)

an scoil the school 'sc' not lenited — exception!

Phase 2

Feminine vowel-initial nouns — no mutation

Feminine nouns starting with a vowel cannot be lenited — you cannot insert 'h' after a vowel. So they take plain an with no mutation. This means they look the same as masculine nouns after the article, but they are feminine and follow feminine rules in all other contexts (genitive case, adjective agreement, eclipsis triggers).

an oíche the night Feminine, vowel-initial → no mutation

an t-uisce the water Masculine, vowel-initial → t- prefix

To tell which is which, you need to know the noun's gender — which is why memorising gender alongside each word from the start is so important.

Phase 3

Coming in Phase 3: Eclipsis (urú)

Eclipsis replaces the initial consonant entirely: b → mb, c → gc, d → nd, f → bhf, g → ng, p → bp, t → dt. Vowel-initial words take an n- prefix. Triggered by prepositions like ar an, ag an, and others.

Phase 3

Coming in Phase 3: The Genitive Case

The genitive case expresses possession and is used after many prepositions. Each declension class has its own genitive formation pattern. Example: leabhar an fhir — the man's book.