Caibidil a hAon: The Noun (an tAinmfhocal)

Im Irish there are 5 cases: the 4 like those in German as well as the vocative as the 5th case. Iin the official standard there are supposedly only now 3 cases, whereby nominative, accusative and dative are combined. The dative has, however, often its own forms and even if the form of the cases is the same, there are other rules for lenition and eclipsis, therefore, it is not practical/possible to do without the dative. Nominative and accusative are always the same, so that even defenders of the dative don't see the accusative any more as an autonomous case, so that 4 cases remain: nominative/accusative, genitive, dative and vocative. Here, all 5 cases are described, because they are also discussed singly in Irish language grammar references in Irish. In Irish grammar books in English, the nominative/accusative/dative are combined as the "common case".

the nominative (an tuiseal ainmneach):

The nominative is used as the subject of a clause. Additionally it is used as the subject and predicative noun of a copular clause.
Nominative- and accusative forms are identical.
The dative form is also, with a few exceptions, identical to the the nominative form.
In the dialects, often non-standard dative forms are also used in the nominative (e.g. Éirinn instead of Éire, in Conamara e.g. bróig instead of bróg)

The nominative is used with the following prepositions: seachas, go dtí
(both contain a verb form, whose subject is the noun in the nominative: seachas = seach + is, go dtí = "until coming")

nominative singular (ainmneach uatha)

This is the base form, as one would find in the dictionary.

nominative plural (ainmneach iolra)

Forming the plural (iolra) is even in the standard quite irregular, and that it is often different in the dialects, this makes the matter even more difficult.
Basically, one can speak of two different ways of forming the plural :

the weak plural (an lagiolra):

This is almost exclusively present in the 1st + 2nd declension, but is quite common.

1st declension: nominative plural = genitive singular e.g.: leabhar - leabhair
or: plural suffix -a e.g. cleas - cleasa
2nd declension: plural suffix -a e.g.: bróg - bróga

It is called weak, because only the stem is modified in the plural, a stem-supplementary (consonant containing "real") plural suffix is not present. The plural forms are different in the genitive ( = nom. sing.) and sometimes also in the vocative( suffix -a).
In some dialects, instead of the the weak plural form, strong plural suffixes are often given preference (e.g. nasc-nascanna instead of naisc)

the strong plural (an tréaniolra):

It is formed by adding different suffixes:
e.g.: í, -acha, -anna, -tha etc. (e.g.: bás - básanna)

It is called strong, because the stem in the plural is "supplememnted" with additional consonants (-í was formerly written -idhe).
The consonants of the plural suffix are used in all cases, although formerly modified (e.g.: nominative/accusative -anna, genitive -ann, dative -annaibh), though today in all cases (nominative, genitive, dative and vocative) unchanged (e.g.: -anna).
Originally, these suffixes were limited to certain declensions (e.g. -acha for nouns of the 5th decl. mit -ach im genitive, -anna auf jene mit -ann im genitive), they spread out in Modern Irish over the other declensions.
Their "popularity" is due to the clarity of the tagging as a plural, comp. naisc (weak plural ) with nascanna (strong plural ).
Often, different plural suffixes are used, partially also seemingly several plural suffixes: In Connacht e.g. -thaí (-tha + -í), -annaí (-anna + -í), etc. (where this -í is probably the dative-plural suffix -ibh, spoken in Connacht as [i:])

nominative dual (ainmneach déach)

Not to remain unmentioned that in Irish there are still traces of the dual (the pair, an déach).
It occurs only following the number 2 (dhá).

The dual form (not only in the nominative, but in all cases, also in the genitive-dual and dative-dual) is always the same as the dative-singular:
e.g.: cos = a foot (nominative-singular), cosa = feet (nominative-plural )
ar an gcois = on the foot (dative-singular),
dhá chois = two feet (nominative/genitive/dative-dual)
In the genitive-dual, the genitive-plural form can also be used (where the genitive following a number is rather atypical)
see also footnote in Chapter 11 (Numbers)

the genitive (an tuiseal ginideach):

use of the genitive

• noun as the attribute of another noun
  genitive attributives always follow the definite noun. They resemble attributive adjectives.
  In German there are often compounds instead of a genitive.
  The meaning of the attributive can be:
  • partiality (partitive genitive): cuid airgid = a share of the money
  • origin: mac Sheáin = the son of Seán
  • ownership, membership: teach an fhir = the man's house
  • material: teach adhmaid = wooden house ("house [of] wood")
  • contents: bosca chíste = cake box ("box [of] cake")
  • specific purpose: fear an tí = man of the house
  • description: lá Nollag = December day ("day [of] December")
  • use: bróg cailín = girls' shoe
  • title, name: Scoil Bhríde = Brigid School
  • monetary value, age, other measurements: stampa scillinge = 1 shilling stamp, leanbh bliana = one-year-old child ("child [of one] year")
  • Apposition: some genitives are called appositions, often to specify gender: baintreach fir = widower ("widow [of] man" > "widow+man" > "male widow"), dochtúir mná = female doctor("doctor [of] woman" > "doctor+woman" > "female doctor"), macaoimh mná = young woman ("young person [of] woman" > "female young person")
  • object of transitive action:
    After a noun that denotes a transitive action, always the object of the action takes the the genitive, not its subject:
    grá Dé = the love for God (not: the love of God! In German the form "die Liebe Gottes" would more mean the latter!)
  • subject of intransitive action:
    Only after nouns, that describe intransitive (objectless) actions, can one use the genitive to describe the subject:
    imeacht na traenach = the departure of the train; seitreach capaill = horse's whinny ("whinny [of the] horse")
• noun as the object of the verbal noun
  • definite noun after the verbal noun:
    Tá sé ag déanamh na hoibre = He is doing the work ("He ist at doing the work")
  • indefinite noun after the verbal noun, when it has no further attribute:
    Tá sé ag cur báistí = It's raining ("it is at laying [a] rain")
  • noun with the preposition a (= "zu")that comes before the verbal noun, when the verbal noun itself is the attribute of another nouns (in Ger. most Partizip I); see also verbal noun as an attributive:
    fear na mná a phógadh = the man that is kissing the woman ("man that woman to kiss")
• noun following definite prepositions
  • after the genitive prepositions (originally nouns) trasna, chun, cois, timpeall, fearacht, tar éis
    e.g.: trasna an ghoirt = across the field ("across of the field")
  • after derived prepositions (that contain nouns) e.g. ar aghaidh = in front of ("on face")
    e.g.: ar aghaidh an tí = in front of the house ("on face of the house")
• after quantities (see partitive genitive)
  • after nouns like mórán (much), beagán (little), neart (a bit), roinnt (some), dóthain (enough), breis (further), cuid (share) e.g. roinnt bainne = some milk
  • after adverbs like go leor (a lot, enough), níos mó (more) e.g. níos mó bainne = more milk
• nouns, esp. the verbal noun, forming participles, mostly with the prefixes so-, do-, in-. With regular nouns, today this is rare, and with a verbal noun, the genitive is often equivalent to a verbal adjective, hence the details are there(see verbal adjectives).

• when two nouns in the genitive directly follow one another, to avoid a double genitive
  Instead the first is lenited in the nominative and only the second is in the genitive. This is the so-called "functional genitive", the first noun is "functional" in genitive relation, but keeps the nominative form and is lenited.
  
  • This is always the case, if the 2nd noun is definite:
    e.g.: teach mhac Sheáin (the house of the son of Seán) but teach (an) mhic = the house of (the) son (genitive)
  • If the 2nd noun is indefinite, a double genitive is also possible:
    e.g.: seol an bháid adhmaid = the sail of the wooden boat ("sail of the boat [of] wood")
  • If the 1st noun is a verbal noun, it is then always in the genitive (see verbal noun as the attributive)
    e.g.: lucht foghlamtha na Gaeilge = the Irish learners ("people [of the] learning of Irish")
  • If the noun describes a quantity (e.g. neart, roinnt, cuid, etc) and if a partitive genitive follows the dative. e.g.: Tá sé ag ól roinnt bainne = He's drinking some milk
• with nouns as the object of the verbal noun
  • if an indefinite noun follows the verbal noun and is given a further attribute. e.g.: Tá sé ag léamh leabhar maith = He is reading a good book (see asldo genitive with the verbal noun)
  • if a noun with the preposition a (= "zu") precedes the verbal noun in infinitive constructions ("infintiv with to"), rather the accusative.
    e.g.: Ba mhaith liom cluiche a imirt = I would like to play a game ("would be good with-me, a game to play")
  • if a verbal noun is the object of another verbal noun. Instead, as in German, in infinitive construction is used:
    e.g.: ag iarraidh fiafraí = trying to ask
• with nouns + numbers
  • nouns following cardinal- and ordinal numbers (only after 1 or 1st is the genitive possible, but not after 11 etc.)
    e.g.: teach an dara fear = the house of the second man, stampa dhá scilling = 2 shilling stamp
  • nouns followed by numbers or letters as numbers (roth bus a haon = the wheel of bus nr. 1)
• with feminine proper names, if they have an adjectivial attribute or stand next to a surname:
  e.g.: teach Bhríd Rua = the house of the red-haired Bríd, teach Bhríd Ní Cheallaigh = Bríd Kelly's house (aber: teach Bhríde = Bríd's house)
• after the noun cúpla:
  e.g.: Tá sé ag ól cúpla deoch. = He is drinking a few drinks.
• after prepositions, that actually require the genitive
  • if the noun is part of an infinitive construction.
    e.g. le linn an cluiche a bheith ar siúil = while the game was on (no genitive) but le linn an chluiche = during the game (genitive)
  • if a verbal noun comes directly after a derived preposition.
    e.g.: le linn dul abhaile = on the way home (see also genitive + verbal noun)
  • if a verbal noun comes directly after chun in the sense of in order to .
• depending on the dialect sometimes the genitive is left aside [ 1 ]

the partitive genitive and the partitive dative (an ginideach rannaíoch agus an tabharthach rannaíoch)

• the genitive can specify a part of the whole. This is the partitive genitive (in German, one uses the nominative instead of the genitive)
  e.g. roinnt airgid = some money (lit.: "a share of money"), ceathrú úill = a quarter of an apple
• Instead one can choose to form this by a definite noun of the partitive dative with the preposition de + article ( in German there would be here rather the partitive genitive!). This is especially so if the first noun should remain indefinite:
  e.g.: cuid den airgead = a share of the money("part of the money"), ceathrú den úll = quarter of the apple ("from the apple"), roinnt de na fir = some of the men ("share of the men")
• The partitive dative ist always necessary, if both nouns are definite (also here one would use the genitivein German): mo chuid den airgead = my share of the money ("my part of the money")

particulars of definite genitive-attributives

• In the definite genitive-attributives, the antecedent itself counts as definite. So it is not allowed to become definite itself (e.g. by adding an article or a possessive pronoun)!
  e.g.: teach an dochtúra = the house of the doctor (nicht: a house of the doctor!)
  teach m'athar = the house of my father (nicht: a house of my father!)
  teach Sheáin = John's house (nicht: a house of Johns!)
  (This is equivalent to the German W suffixes like "Johns Haus", or "des Kaisers Bart", where the genitive attribute is definite and through this also the antecedent becomes definite; as opposed to: "der Bart des Kaisers", where both nouns have to carry the article)
• Combinations of a definite genitive attribute with an indefinite remaining antecedent are also not possible (e.g. a house of the doctor). Here one needs instead a dative: e.g. teach don dochtúir = a house of the doctor, lit.: "a house to-the doctor"

genitive singular (ginideach uatha)

• The formation of the genitive occurs in various ways.
  Through this, the declension groups differentiate themselves from one another. Te formation is (relatively) simple and regular (provided, one knows to which declension group a word belongs to)

genitive plural (ginideach iolra)

• = nominative-singular with the weak plural
  In the standard, this encompasses most of the nouns of the 1st declension
  e.g.: an fear - na bhfear (the man - of the men),
  as well as many of the 2nd declension nouns (but often depalatalised!)
  e.g. an bhróg - na mbróg (the shoe, of the shoes); an tsúil - na súl (the eye, of the eyes)
• = nominative-plural with the strong plural
  Here are mostly the nouns of the 3rd and 4th declension, most of the 5th , some of the 2nd and 1st declension.
  e.g.: an cailín - na cailíní - na gcailíní (the girl- the girls- of the girls) [ 2 ]
• = genitive-singular, Here are some of the nouns of the 5th declension (with the genitive singular on -n, -d)
  e.g.: an cara - an charad - na gcarad (the friend- of the friend- of the friends)
  in some exceptions also with the genitive singular on -ch: na caorach - na gcaorach (of the sheep, of the sheep)
• autonomous Form (exceptions)
  e.g.: bean - ban

lenition / eclipsis in the genitive

• indefinite nouns:
  To simplify, one could say that indefinite genitive attributives act like attributive adjectives (s.a. lenition of adjectives)

  unlenited after masculine nouns in the nominative singular
  e.g. fear céile = husband
  lenited after masculine nouns in the weak plural (on slender consonants)
  e.g. na fir chéile = the husbands
  lenited after masculine nouns, that are in the genitive themselves (on slender consonants)
  e.g. an fhir chéile = of the husband, teach pobail bhaile = the church of a town
  lenited after feminine nouns in the nominative singular
  e.g. bean chéile = wife
  especially:

  • after femin. nouns of quantity: punt phrátaí = 1 pound of potatoes
  • genitive of the verbal nouns: bean chaointe = wailing woman
  • with the appositive genitive (animals and things): cráin mhuice = the sow of the pig
  • with the genitive of material: tine mhóna = turf fire

  unlenited after feminine nouns:

  • with the partitive genitive (part of, lack of, excess of...) roinnt bainne = some milk
  • with the appositive genitive (with people): baintreach fir = widower ("male widow")
  • with the genitive of category (with people): bróg cailín = girls' shoe ("shoe for a girl")
  • with genitive of action: seitreach capaill = horse whinnying
  • with body parts or parts of things: láimh duine = human hand
  • after a fem. verbal noun, if following a preposition (mostly): ag iarraidh comhairle = to ask for advice
  • after a fem. verbal noun, if used as an indefinite regular noun
  • after abstract nouns, e.g.: saoirse cainte = freedom of speech
  • after collectives, if it's the genitive plural : buíon fear = a troop of men
  • if the noun in the genitive has an attribute: bean baile mhóir = big-city woman (but: bean bhaile)
  • after derived prepositions e.g. in aghaidh múinteora = against a teacher

• article-carrying definite nouns
  The rules are defined by the article.

  lenited: after a masculine genitive-singular-article (an) (e.g. teach an fhir = the man's house
  unlenited: after a feminine genitive-singular-article (na) (e.g. teach na mná = the woman's house)
  eclipsed: after a genitive-plural-article (na) (e.g. teach na bhfear, teach na mban = the men's house, women's house )

• possessive pronoun-carrying definite nouns
  again the rules are defined by the possessive pronoun.

  lenited after mo, do, a (masc.) (e.g. rogha a chairr = the wheel of his car)
  unlenited after a (fem.) (e.g. rogha a cairr = the wheel of her car)
  eclipsed after ár, bhur, a (plur.) (e.g. rogha ár gcairr = the wheel of our car)

• proper names and other definite nouns in the genitive

  principally lenited (e.g. fear Cháit = Kate's man)
  Not lenited: names with: Mo.., Do... (both former vocative forms), Maol...
  Not lenited: words like: Dé = of God, San = Saint. e.g.: glóir Dé = the Glory of God
  Not lenited: names of saints after: Féile = festival, San = Saint, Naomh = Holy e.g.: Lá Fhéile Pádraig = St. Patrick's Day
  Not lenited: foreign names, e.g.: dán Goethe = Goethe's poem

• after genitive prepositions

  indefinite nouns after chun, dála, timpeall, fearacht, trasna are mostly unlenited

the dative (an tuiseal tabharthach):

use of the dative:

• It is used as the indirect object  after most simple prepositions:
  a, ag, ar, as, chuig, de, do, faoi, go, i, ionsar, le, ó, os, roimh, thar, trí, um (and in the plural after idir)
• as opposed to German, in Irish, a dative object without a preposition is not possible.
  If in German the dative without preposition would appear, in Irish often one must use the preposition do (= to) : comp.:
  • Ich gebe das Buch der Frau =I give the woman the book = irisch: Tugaim an leabhar don bhean (lit.: "...to the woman")
  • Ich gebe dir das Buch; = I give you the book= irisch: Tugaim an leabhar duit (lit.: "...to you")
• a differentiation of the static locative (dt. dative: "in der Schule"=in the school) from the dynamic locative (dt. accusative: "in die Schule"=into the school) is not common anymore in Irish [ 3 ]
  This is independent of if a special dative form or the nominative form is used: sa tigh = in the house/into the house or. sa teach = in the house/into the house
• the dative with le and do is used for personal relationships, similar to German "von", to express an indefinite person: e.g.: deartháir le Seán = a brother of Seán's, uncail dóibh = an uncle of yours, cara dom = a friend of mine
  (instead of the genitive for definite persona: deartháir Sheáin = Seán's brother, bhur n-uncail = your uncle, mo chara = my friend)
• similar with le to show ownership/copyright of an indefinite object: dán le Goethe = a poem by Goethe (as opposed to the genitive: dán Goethe = Goethe's poem)
• The partitive dative (an tabharthach rannaíoch) with the preposition de is often useds in place of the partitive genitive (see also there), to identify a part or a quantity of things:
  cuid den obair = share of the work, beirt de na mná = two of the women
• the dative of the agent, dativeus auctoris (an tabharthach gníomhach) acts as the logical subject of some clausal constructs without a grammatical (nominative-) subject, see subjectlessness. e.g.: Is as Dóire dom = I'm from Derry, le linn gloine a ól dom = while I drink a glass
• additionally, the dative form, if available, appears after the number 2. Actually, this is the nominative of the duals (an déach), which has the same form as the dative-singular. e.g.: dhá bhróig = two shoes, a dhá cois = her two feet

autonomous dative forms:

• An autonomous form hardly has the dative in the standard anymore.
  This is similar to German, where dative forms also sway (vgl. dem Manne / dem Mann)=the man's/of the man.
• This is why, today at least, the dative form = nominative form
• In the official standard there are also still common dative forms (5 words of the 2nd declension,  Éire is the 5th decl.):
  cos-cois (foot), lámh-láimh (hand), bróg-bróig (shoe), bos-bois (palm), cluas-cluais (ear),
  Éire-Éirinn (Ireland),
• some words appear in definite set W suffixes in the old dative form:
  ceann-cionn (= head e.g. in os cionn = above), ciall-céill (sense e.g. in cur i gcéill = to convince, to bring sense (to s.o.))

dative singular (tabharthach uatha)

The dative of all nouns in the 2nd declension (not only the 5 above mentioned words) is formed via palatalisation: e.g. bróg-bróig, fearg-feirg, fuinneog-fuinneoig, teach-tigh
The dative of the 5th declension with the genitive on a borad -n or -d is formed palatalisation of the genitive: e.g.: Éire (Nom.)-Éireann (Gen.)-Éirinn (Dat.), fiche (Nom.)-fichead (Gen.)-fichid (Dat.)

Often, these dative forms of both declensions appear instead of the nominative:
e.g. Éirinn colloq. much more common than the official Éire = Ireland, today always Albain instead of Alba = Scotland, abhainn instead of abha = river
in Connemara bróig instead of bróg, fuinneoig instead of fuinneog (words of the 2nd decl.) in the nominative.

In the1st , 3rd and 4th declension, the dative form is, since a long time, always the same as the nominative form.
In the 1st declension, some dative forms in a few set W suffixes (as mentioned above: ceann = head- os cionn = overhead ) are maintained. (the dative was once formed via "u-colouration" of the final consonant)

The dative irregular nouns: the dative of bean ist mnaoi, that of lá is ló (e.g. sa ló = per day)

dative plural (tabharthach iolra)

The dative plural of all declensions is formed with the addition of the suffix -ibh. (originally related to the latin suffix -ibus, comp.: viribus = the men) (e.g. fear-fearaibh, bróg-brógaibh etc.).

The form depends on the nominative-plural , independent of the other declension:

lenition / eclipsis in the dative

without article:
After ag, as, chuig, fara, le there is neither lenition nor eclipsis.
After ar, de, do, faoi, ionsar, ó, roimh, trí, thar, um one lenites (general terms do not follow after ar and thar)
After i one eclipses. (also after the today rarer iar = after, go = with)

with the singular-article:
In the standard, for most prepositions there is a choice, either lenition (common in Ulster) or eclipsis (in Munster and Connacht) (ar an mbád or ar an bhád = on the boat)
After den (de + an), don (do + an) and sa(n) (i + an) the standard lenites (den chathaoir = of the chair, san fharraige = in the sea)
d, t, s are neither lenited nor eclipsed (den doras = of the door, ar an doras = on the door, don sagart = to the priest)
Feminine nouns beginning with s (+ vowel or l, n, r) receive a t- prefix (ar an tsráid = on the street)

In the dialects, lenition and eclipsis are governed by different rules (see also the overview article and preposition)

with the plural article
No lenition or eclipsis.

the accusative (an tuiseal cuspóireach):

The accusative form is always the same as the nominative form.
The rules of lenition and eclipsis are, as well, same as in the nominative.
So can one tell the accusative from the nominative - only via the function/syntax.

the accusative is used with a direct objecten of a verb and of the clause:
e.g.: Chonaic mé an fear = I saw the man (direct accusative object: an fear)
The direct object of the verbal noun is in the accusative, if it precedes it and is connected to a = to.
e.g.: an fear a fheiceáil = to see the man
As in German, the accusative is used in adverbial time expressions
e.g.: Bhí mé ann an oíche sin / an bhlian seo caite = I was there last night/ last year (accusative-time expression: an oíche sin or. an bhliain seo caite)

Aside from those, the following prepositions require the accusative: ach, gan, idir, mar, ná
idir requires the dative with nouns in the plural (there, idir has more the meaning of "among": idir mná = among women)

the vocative (an tuiseal gairmeach)

use of the vocative

The vocative form is not used by nouns and adjectives (but always the vocative particle), if

• the terms of inanimate objects are used as a name for people (a stór! = Darling) and
• In the case of collectives (a phobal = People!)
• if a definite noun follows in the genitive: a mhac Bhriain = Son of Brian! (except in certain terms and proper names: a Mhic Dé = Son of God!, a Mhic Bhriain = Mr. MacBrien!)

formation of the vocative:

• nouns: always with vocative particle and always lenited (if possible)!
  e.g.: a Sheáin = Seán!
  The vocative particle doesn't have the acclamatoric meaning of the German/English "O/oh!", it is rather unstressed and flown over. As a stressed appell in Irish, one can, in addition to the vocative particle, use the word ó (following) : (a Sheáin ó = oh Seán!)
• the use of the possessive pronoun in the form of address (like in English: e.g. my friend!) is not common (a chara = (my/dear) friend!) except sometimes in the religious setting: ár nAthair atá ar Neamh = Our Father, who art in Heaven...
• also appositive personal pronouns in the form of address (in English e.g. you Idiot!) are not common (a amadáin = Idiot!)

vocative singular (gairmeach uatha)

• 1st declension: vocative = genitive singular  (e.g. fear - a fhir = man!)
• 2nd -5th declension: vocative = nominative singular (e.g.: cailín - a chailín = girl!)
• following adjectives that are attributive are always lenited
• after masculine nouns (1st -5th declension!) adjective form = genitive singular, (e.g.: a fhir mhóir = big man!)
• after feminine nouns adjective form = nominative singular (a bhean mhór = big woman!)

exceptions:

• Ó in names in the vocative form = Uí  (after that, lenition, h- entfällt)  e.g.: a Phóil Uí Shé! = Paul O'Shay!
• Mac in names in the vocative form = Mhic (after that, lenition, c after Mhic is not lenited) e.g.: a Sheáin Mhic Sheamais! = Seán McHamish!
• mac vocative form = a mhic! or also a mhac! ("Son!")
• leanbh  vocative form = a linbh! or a leana! ("Child!")
• Mícheál vocative form = a Mhícheáil! or a Mhíchíl!

vocative plural (gairmeach iolra)

• weak plural   vocative = nominative singular + suffix a
  (e.g. a fheara! = Men!)
• strong plural : vocative = nominative plural
  (e.g. a bhuachaillí = Boys!)
• following adjectives remain always unlenited, the form is the same as the nominative plural
  (e.g.: a fheara Gearmánacha! = German men!)
• following other attributives remain as well unlenited
  (e.g. a fheara céile = Husbands!)

Apposition (Comhaisnéis)

• In the case of title + surname, the surname is always in the same case as the title.
  e.g. genitive: teach an Athar Uí Anluan = the house of Father Ó hAnluan, vocative: Dia dhuit, a Athair Uí Anluan = Hello, Father Ó hAnluan!
• In the case of title + first name (+ surname) the name remains in the nominative, only the title is declined.
  e.g.: an Bráthair Seán Ó Cléirigh = Brother Seán O'Cleary, teach an Bhráthar Seán Ó Cléirigh = Brother Seán O'Cleary's house
• In the case of first name + noun the noun remains in the nominative.
  e.g.: leabhar Sheáin gabha = Seán the blacksmith's book, teach Phóil, mac an dochtúra = Paul the son of the doctor's house
• In the case of two titles the 2nd title is in the genitive (appositive genitive), but the article comes before the first title:
  e.g.: an Tiarna Easpaig = Lord Bishop (lit.: "the lord [of a] bishop")
• as well, the appositive genitive appears actually with 2 regular nouns. (see under genitive, e.g. baintreach fir = widower [widow + man], múinteoir mná = female teacher [teacher + woman]). Aside from such formations, today, mostly the 2nd noun remains in the nominative.
• Often instead of an apposition, a copular relative clause ("who is..."):
  e.g. an t-amadán is mac duit = your son, the fool (lit.: "the fool, that your son is")
  or also a dative with de:
  amadán de mhac = an idiot of a son, gliogar de chathaoir = a cripple to the chair )
• If a personal pronoun stands with a noun in apposition, a preposition is with both: e.g. léi leis an mbanríon = with her, the queen

definite nouns (ainmfhocail chinnte)

1. it is with the article e.g.: an fear = the man
2. it is with a possessive pronoun e.g.:  bhur bhfear = your man
3. it occurs with gach (every) e.g.: gach fear = every man
4. it is numerated , e.g.: fear a haon = man Nr.1
5. i is a proper name, e.g. Seán
6. it is a unique place or person (then always without article) e.g. neamh = Heaven, ifreann = Hell, Dia = God
7. it's carrying anoter definite noun as the genitive attributive e.g. teach an dochtúra = the house of the doctor, teach Sheáin = the house of Seán's
   (see particulars of the definite genitive attributive)
8. it's in the vocative e.g.: a fhir = man!

[ 1 ]
Ó Siadhail in "Learning Irish" states that for the Cois-Fhairrge-dialect (Connacht)only then the genitive is used, if the noun is definite and after quantities, otherwise nominative (lenited only, if a further attribute follows)
All in all, even the genitive seems to be disappearing more and more, nominative forms are seen as a replacement not only in the singular but also in the plural.
[ 2 ]
Earlier, there were autonomous genitive plural forms for nouns with the nom. pl. ending in -anna: -ann and for nouns of the 4th declension ending in -í (-idhe): -eadh (an cailín - na cailínidhe - na gcailíneadh)
[ 3 ]
Earlier, there was a difference between dative and accusative after prepositions (location vs. direction)
comp. the adverb, stemming from a contraction isteach = inside (lit.: "into the house") and istigh = inside (lit.: "in the house"). As well: amach = outside and amuigh = outside (eigtl. i mach = into a field and i maigh = in a field)
According to O'Nolan, the use of eclipsis after a preposition and article is a sign of the accusative use in the sense of motion (e.g.: ar an mbord = on to the table, as opposed to lenition (ar an bhord) as a sign of the dative of location (= on the table). This differentiation has been lost, now depending on the dialect one either just lenites or just eclipses.