IRISH-GAELIC GRAMMAR:  VERBS

Most Gaelic verbs are “regular,” meaning they have a predictable set of conjugations that correspond to the paradigm of 1st person, 2nd person, 3rd person (m.), 3rd person (f.), in both singular and plural.  There are eleven irregular verbs (“to be” and ten others).  The challenge in understanding verbs is in discovering the root and conjugating it appropriately.  In your dictionary, all verbs are conjugated under the 2nd person imperative (“Bí ciúin!” = “You be quiet!”).  Verbs come in two types: roots having one syllable (type 1) and roots having two syllables (type 2).  A verb’s type determines its ending in each conjugation.  In the following examples in the context of sentences, #1-4 are type 1 (one-syllable root, such as glan/clean), and #5-8 are type 2 (two-syllable root, such as oscail/open).  Use any verb in place of “to be” at the beginning of a sentence.  The examples selected below are a rough guide to verbs, but you can guess what the root of a verb is by looking at the first several letters and then looking them up.

PART ONE:  THE MOST IMPORTANT VERB TO KNOW!

TO BE:  This is the most common verb for most beginners of Irish, and it is good to know how it works prior to proceeding to the more complicated verb forms of the others.

tá = present tense, positive (is)
níl = present tense, negative (isn’t)
an bhfuil = present tense, interrogative (is?)
nach bhfuil = present tense, negative interrogative (isn’t?)

bhí = past tense, positive (was)
ní raibh = past tense, negative (wasn’t)
an raibh = past tense, interrogative (was?)
nach raibh = past tense, negative interrogative (wasn’t?)

beidh = future tense, positive (will be)
ní bheidh = future tense, negative (won’t be)
an mbeidh = future tense, interrogative (will be?)
nach mbeidh = future tense, negative interrogative (won’t be?)

bíonn = habitual tense, positive (does be)
ní bhíonn = habitual tense, negative (doesn’t be)
an mbíonn = habitual tense, interrogative (do be?)
nach mbíonn = habitual tense, negative interrogative (doesn’t be?)

cá bhfuil = present tense, locative (where is?)
cá raibh = past tense, locative (where was?)
cá mbeidh = future tense, locative (where will be?)
cá mbíonn = habitual tense, locative (where does be?)

Examples:
Locative
Cá bhfuil tú ag dul?  Where are you going?
Cá raibh tú ag dul?  Where were you going?
Cá mbeidh tú ag dul?  Where will you be going?
Cá mbíonn tú ag dul?  Where do you be going [each day]?

Present
Tá tú ag ól tae.  You are drinking tea.
Níl tú ag ól tae.  You are not drinking tea.
An bhfuil tú ag ól tae?  Are you drinking tea?
Nach bhfuil tú ag ól tae?  Aren't you drinking tea?

Past
Bhí siad anseo inné.  They were here yesterday.
Ní raibh siad anseo inné.  They weren't here yesterday.
An raibh siad anseo inné?  Were they here yesterday?
Nach raibh siad anseo inné?  Weren't they here yesterday?

Future
Beidh Gaeilge agam.  I will speak ("have") Gaelic.
Ní bheidh Gaeilge agam.  I will not speak Gaelic.
An mbeidh Gaeilge agam?  Will I speak Gaelic?
Nach mbeidh Gaeilge agam?  Won't I speak Gaelic?

Habitual
Bíonn tú mall.  I do be late [every day]
Ní bhíonn tú mall.  I do not be late [every day]
An mbíonn tú mall?  Do you be late [every day]?
Nach mbíonn tú mall?  Don’t you be late [every day]?

PART TWO:  THE REGULAR VERBS

PRESENT TENSE -- is  (corresponds to tá):
A regular verb in the present uses the same verbal particles (an/nach to ask a question, etc.) as with tá.  So “An bhrisim an chathaoir?” means “Do I break the chair?” “Ní bhrisim an chathaoir” means “I don’t break the chair,” etc.  Ní lenites the verb.
TYPE 1:  glan (clean)			TYPE 2:  oscail (open)
glanaim	glanaimid		osclaím		osclaímid
glanann tú	glanann sibh		osclaínn tú	oscleann sibh
glanann sé/sí	glanann siad		oscleann sé/sí	oscleann siad

PAST TENSE -- was  (corresponds to bhí):
The past tense is lenited, except for consonants that don’t lenite (l, n, r, etc.).  For vowels, put d’ in front of the verb (see #7 and 8 below). Ní (used for irregular verbs) and níor (regular verbs) lenite the verb.
TYPE 1:  glan (clean)			TYPE 2:  oscail (open)
ghlan mé	ghlanamar		d’oscail mé	d’oscailamar
ghlan tú	ghlan sibh		d’oscail tú	d’oscail sibh
ghlan sé/sí	ghlan siad		d’oscail sé/sí	d’oscail siad

NEGATIVE AND INTERROGATIVE PAST TENSES
A regular verb in the past uses níor (in place of ní), ar (in place of an), nar (in place of nach), and gur (in place of go).  
Léigh Cáit an leabhar.			Kate read the book.
Níor léigh Cáit an leabhar.		Kate did not read the book.
Ar léigh Cáit an leabhar?		Did Kate read the book?
Nar léigh Cáit an leabhar?		Didn’t Kate read the book?
Deir siad gur léigh Cáit an leabhar.	They say that Kate read the book.
Deir siad nar léigh Cáit an leabhar.	They say that Kate didn’t read the book.

HABITUAL PRESENT -- does be (corresponds to bíonn):
Ní lenites the following verb.  (Ní bhriseann sí an chathaoir.)
TYPE 1:  glan (clean)				TYPE 2:  oscail (open)
glanann mé		glanaimid		osclaím			osclaímid
glanann tú		glanann sibh		osclaíonn tú		osclaíonn sibh
glanann sé/sí		glanann siad		osclaíonn sé/sí		osclaíonn siad

FUTURE TENSE -- will be (corresponds to beidh):
Roots with one syllable add -f(a)idh (“e”); roots with two syllables add -óidh or -eoidh (“e”).  Ní lenites the following verb (Ní bhrisfidh sí an chathaoir).
TYPE 1:  glan (clean)			TYPE 2:  oscail (open)
glanfaidh mé	glanfaimid		osclóim		osclóimid
glanfaidh tú	glanfaidh sibh		osclóidh tú		osclóidh sibh
glanfaidh sé/sí	glanfaidh siad		osclóidh sé/sí		osclóidh siad

CONDITIONAL TENSE -- would be (corresponds to bheadh):
TYPE 1:  glan (clean)				TYPE 2:  oscail (open)
ghlanfainn mé		ghlanfaimis		d’osclóm		d’osclómis
ghlanfainn tú		ghlanfainn sibh	d’osclódh tú		d’osclódh sibh
ghlanfainn sé/sí	ghlanfainn siad	d’osclódh sé/sí		d’osclódh siad

HABITUAL PAST -- used to be (corresponds to bhíodh):
Ní lenites the following verb.
TYPE 1:  glan (clean)				TYPE 2:  oscail (open)
ghlanainn 		ghlanaimis		d’osclaíoinn		d’osclaíomis
ghlantá			ghlanadh sibh		d’osclaíodh tú		d’osclaíodh sibh
ghlanadh sé/sí		ghlanaidís		d’osclaíodh sé/sí	d’osclaíodís

IMPERATIVE -- do this! (corresponds to bí):  Negation is with ná.
Glan/Glanaigí an bord!		Clean/Y’all clean the table!
Nigh/Nígi na soithí!			Wash/Y’all wash the dishes!
Léigh/Léigí an leabhar!		Read/Y’all read the book!
Oscail/Osclaígí an doras!		Open/Y’all open the door!

VERBAL ADJECTIVE -- is done (passive voice):
This would be glanta (is cleaned), nite (is washed), léite (is read), etc.
Tá an bord glanta.			The table is cleaned.
Tá na soithí nite.			The dishes are washed.
Tá an leabhar léite.			The book is read.
Tá an chathaoir briste.		The chair is broken.

PART THREE:  THE IRREGULAR VERBS

These you just have to memorize.  They are plagued by regional variation too.
English	imp.sing.	verbal n.	all habitual	fut/cond	past tense
1. hear		clois		cloisteáil	clois-		clois-		chuala
2. eat		ith		ithe		ith-		íos-		d’ith
3. give		tabhair		tabhairt		tug-		tabhar-		thug
4. give birth	beir		breith		beir-		béar-		rug
5. say		abair		rá		deir-		déar-		ráite
6. come	teara		teacht		teag-		tioc-		tháinig
7. make/do	déan		déanamh	déan-		déan-		rinne	
8. see		feic		feiceáil		feic-		feic-		chonaic
9. go		gabh		goil		té-		gabh-		chuaigh
10. get/find	faigh		fáil		faigh-		gheobh-	fuair