An Caighdeán Oifigiúil: Chapter 10: Initial Mutations (pp. 171-202)

10.1 General

An initial mutation is a change that is made to the start of a word due to gender, case, tense or other grammatical pretext. Initial mutations include lenition, eclipsis, t before a vowel, t before s, h before a vowel and d’ before a vowel or before fh-. Explanations are given here on the use of initial mutations, including lenition of an indefinite noun after a feminine noun and lenition of an indefinite noun after a plural noun ending in a slender consonant.

Lenition

The lenitable consonants are: b,c,d,f,g,m,p,s (except sc-, sf-, sm-, sp-, st- and sv-) and t.

10.2 Lenition of Nouns

Nouns are lenited in the following instances.

10.2.1 After the Article

A noun is lenited after the article (unless its first consonant is d, t or s):

(a) in the nominative feminine singular, e.g. an chathair; an ghloine; an fhuascailt:

(b) in the genitive masculine singular, e.g. mac an fhir; geata an choláiste:

(c) in the dative singular, masculine and feminine, in certain instances in which a preposition accompanies the article according to the Central System, e.g. den chapall (see 1.4), or the Lenition System, e.g. ar an chapall (see 1.7):

10.2.2 After the Vocative Particle

Lenition follows the vocative particle in the singular and the plural, masculine and feminine, e.g. a dhuine chóir; a Ghaela!; a chairde na páirte:

10.2.3 After Certain Adjectives

Lenition follows the following adjectives:

(a) the possessive adjectives mo, do, a (masculine singular), e.g. mo mhac; do theach; a pheann:

(b) the partitive adjective uile, e.g. an uile fhocal; gach uile sheachtain:

(c) the indefinite adjective aon, e.g. aon mhála, aon chóta (unless the noun begins with d, t or s, e.g. aon duine, aon teaghlach):

10.2.4 After Certain Numbers

Nouns are lenited after the following numbers:

(a) the cardinal number aon and the ordinal number céad, unless the initial consonant is d, t or s, e.g. aon chailín amháin; an chéad bhróg; aon samhradh amháin; an chéad teach:

(b) dhá, e.g. dhá chrann; an dá chóta; except if the possessive adjective a (third person feminine singular and third person plural), ár or bhur precedes, e.g. dhá chapall but a dhá géag (third person feminine singular); ár dhá gcapall; bhur dhá dteach; a dhá mbó (third person plural) (see 8.3.3):

(c) trí, ceithre, cúig, sé, e.g. trí bhád; ceithre bhó (except when the noun has a special plural form after cardinal numbers – see 9.3.2, and for the word cent, e.g. dhá cent; cúig cent):

Note that:

(i) it is the initial mutation that accompanies the final number in a string that is applied to the word subject to it, e.g. sé nó seacht mbád;

(ii) if the Simplified System is used above twenty (see 9.3.10 – 9.3.12), lenition is not applied to the noun, e.g. fiche a trí capall; 56 fuinneog.

10.2.5 After Certain Simple Prepositions

Lenition is applied to nouns after the following simple prepositions:

(a) de, do (and a from do, e.g. obair a dhéanamh), faoi, ionsar, mar, ó, roimh, trí, um, e.g. de Shiobhán; do bhuachaillí; faoi bhord; ionsar Sheán, mar dhuine, ó bhéal:

The prepositions de and do are abbreviated to d’ before a noun beginning with a vowel or f + vowel, e.g. d’athair Sheáin; d’fhoghlaimeoirí Gaeilge; but not before f + consonant, e.g. do Fhrancaigh:

Note: The letters b, m and p are not lenited after um, e.g. ordú um praghsanna a chobhsú; an tÚdarás um Bóithre Náisiúnta.

(b) ar, e.g. ar bhád, ar chlé, ar dheis, ar dhaoine (see also 10.6.4(b)):

Note that the noun is not lenited in the case of adverbial phrases or verbal nouns that express a state or place, e.g. ar ball; ar bord (loinge); ar comhaois; ar comhchéim; ar comhscór; ar comhstádas; ar deireadh; ar fad; ar fiar; ar meisce; ar muir agus ar tír; ar srian; ar tiús; ar bogadh; ar crochadh; ar fáil; ar siúl (with the meaning ‘happening’); but ar fheabhas; ar shiúl (with the meaning ‘gone’). The noun is lenited, however, if it is qualified, e.g. ar chonradh sealadach; ar shaoire mháithreachais; ar bharr an tí; except in the case of ar bord loinge; ar ball beag.

(c) gan, to unqualified nouns whose initial consonant is not d, t, s or f, e.g. gan chuid; gan chiall; gan mhaith; gan mheabhair; gan bhréag; but gan dearmad; gan sagart; gan tine; gan feoirling (exception: gan fhios):

Qualified nouns are not lenited, e.g. gan pingin rua; gan carn aoiligh; gan bolgán solais; gan ciall linbh; gan brí ar bith; gan misneach a chailleadh:

Note that unqualified nouns are not lenited if they are proper nouns, e.g. d’fhág siad gan Cáit; or if they are a verbal noun in a nominal phrase, e.g. b’fhearr duit gan pósadh; moladh dó gan corraí:

(d) idir, when meaning ‘both’, e.g. idir bheag agus mhór; idir chailíní agus bhuachaillí. The noun following agus or is is not lenited if it begins with d, t or s, e.g. idir shúgradh is dáiríre; idir mhná rialta agus sagairt:

Note that nouns following idir are not lenited when it means ‘between’, e.g. idir Corcaigh agus Gaillimh; idir breith agus baisteadh; idir tithe; idir béilí:

(e) thar, e.g. léim sé thar gheata ard; ní raibh thar chúigear acu ann:

Note that nouns following thar are not lenited in certain phrases containing indefinite nouns, e.g. thar barr; thar bráid; thar cionn; thar fóir; thar sáile; thar toinn; nor in the compound preposition thar ceann:

Note: If a string of nouns is subject to a simple preposition, initial mutation is caused only to the noun immediately following it, e.g. Rinne siad taighde ar chonarthaí, comhaontuithe, córais agus scéimeanna; except in the case of idir with the meaning ‘both’, e.g. idir bheag agus mhór.

10.2.6 After Compound Prepositions

A definite noun (see 3.1.2) subject to a compound preposition or cois, dála, fearacht, timpeall, trasna is lenited, e.g. ar aghaidh dhoras an tséipéil; cois Bhóthar na hUaimhe; de bhun mhír (b); fearacht Sheáin; le haghaidh chlár a ceathair:

Note that definite nouns are not lenited after chun, e.g. chun foirgneamh a seacht; chun gairdín a gcomharsan; chun Meiriceá; chun Gearóid; chun Parlaimint na hEorpa.

Indefinite nouns are not lenited except in a handful of old-established phrases, e.g. tar éis bháis (with the meaning ‘after dying’).

10.2.7 After Feminine Nouns

If a genitive noun (that is not definite) is subject to a feminine singular noun (that is not in the genitive), it is typically lenited, e.g. cloch shneachta; deoir bhainne; gloine bheorach; léine chadáis; tuarascáil pharlaiminte; bliain bhisigh; bliain chánach; bliain mheasúnachta; mí ghealaí:

Note that in (a) to (m) below are listed the instances in which an indefinite noun subject to a feminine singular noun (not in the genitive) is not lenited. In all other instances, such nouns are lenited.

Note: It is possible to place some examples in one or more of the cases below, e.g. (b) and (e) both cover the example léim fia.

(a) The second noun is not lenited if the first noun ends in d, n, t, l or s and the second begins with d, t or s, e.g. áit dúchais; bean tí; cúis dóchais; maidin samhraidh; saighead draíochta; scoil samhraidh:

(b) The second noun is not lenited if it begins with f, e.g. buile feirge; cúirt filíochta; deoch fuisce; deoir fola; pailin féir; sochaí faisnéise:

Note that the words beirt and dís are exceptions, in that nouns beginning with f following them are lenited, e.g. beirt fheirmeoirí; dís fhear.

(c) The second noun is not lenited if it is in the genitive plural, e.g. rásaíocht gluaisrothar; saithe beach; scoil cailíní; scuaine gasúr; sraith giorrúchán; táin bó; traein paisinéirí:

Note that the words beirt and dís are exceptions, in that nouns in the genitive plural following them are lenited, e.g. beirt bhan; dís bhreithiúna; and that the phrase clann mhac is too.

(d) The second noun is not lenited if the first noun has an indefinite quantitative meaning, e.g. breis bainne; díobháil céille; easpa tobac; iomarca cainte; roinnt cáise:

(e) The second noun is not lenited if it is (i) a person, (ii) an animal, (iii) a living thing, or (iv) part of a person, animal or living thing:

(i) aghaidh mná; casóg buachalla; culaith garda; lámh cailín; scian búistéara; súil páiste:

(ii) adharc bó; cáis gabhair; coiscéim coiligh; cos capaill; cráin muice; eitinn bólachta; léim capaill; géimneach bó; stail capaill; ubh circe:

(iii) cill planda; coirt crainn; péist cabáiste:

(iv) foinse béil; íde béil; ionga méire; péist goile:

Note that the words beirt and dís are exceptions in that both nouns and people are lenited after them, e.g. beirt bhan; dís bhreithiúna; and céile is lenited after a feminine noun, e.g. bean chéile; deirfiúr chéile.

(f) The second noun is not lenited if the first noun is part of the second noun, e.g. beann píce; cos cathaoireach; cluas cupáin; iall bróige:

(g) The second noun is not lenited if the first is an abstract noun based on an adjective, e.g. áilleacht ceantair; airde balla; breáthacht cathrach; dílseacht pictiúir; finne maidine; sábháilteacht bóthair:

(h) An indefinite noun following a verbal noun preceded by the preposition ag is not lenited, e.g. ag sábháil comhaid; ag tiomáint bus; ag tógáil balla:

Note that there are a small number of exceptions that are old-established, e.g. ag fáil bháis; ag gabháil fhoinn.

(i) An indefinite noun following a verbal noun or a noun expressing an action is not lenited when the second noun is the object, e.g. athchúrsáil gloine; forbairt pobail; láimhseáil ceimiceáin; eisiúint preasráitis:

(j) The second noun is not lenited following the words aicme, comhairle, corparáid, cuideachta, earnáil, feidhmeannacht, foireann, gníomhaireacht, institiúid, oifig, rannóg, roinn, scéim, seirbhís, e.g. aicme ceannais; comhairle contae; corparáid baincéireachta; earnáil gnó; foireann bainistíochta; institiúid breisoideachais; oifig preasa; rannóg pearsanra; roinn cosanta:

(k) The nouns dlí and sí are not lenited after a feminine noun, e.g. feidhm dlí; bó sí:

(l) The second noun is not lenited if it is one of the units of measure bliain, coicís, mí or seachtain, e.g. saoire míosa; tréimhse bliana; moill bliana:

(m) The second noun is not lenited if it is in the genitive and qualified by an adjective or another noun, e.g. oíche gaoithe móire; bileog páipéir dúigh; gloine beorach fuaraithe:

Exception: when the first noun is beirt or dís, e.g. beirt bhan mhisniúla or when beirt is the second noun, e.g. páistí bheirt bhan.

Note that, subordinate to the exceptions in (a) to (m) above, any other noun subject to a feminine noun is lenited, e.g. tuarascáil pharlaiminte agus chomhphobail. If there is a sequence of nouns in a list before another noun, however, the initial mutation accompanying the final noun is the one that is applied to the other noun or nouns subject to it, e.g. leabhar nó iris cheoil; iris nó leabhar ceoil.

10.2.8 After Plural Nouns Ending in a Slender Consonant

If a noun (that is not definite) in the genitive is subject to a plural noun ending in a slender consonant, it is usually lenited, e.g. éin chlóis; dualgais bhreise; ceadúnais ghnó.

Note that in (a) to (f) below are listed all of the instances in which an indefinite noun subject to a plural noun ending in a slender consonant is not lenited. In any other instance, such a noun is lenited.

Note: It is possible to place some examples in one or more of the cases below, e.g. the example dualgais dochtúirí applies to (a), (c) and (d).

(a) The second noun is not lenited if the first noun ends in d, n, t, l, or s and the second starts with d, t, or s, e.g. báid seoil; capaill seilge; turais taighde:

(b) The second noun is not lenited if it starts with f, e.g. beithígh feirme; botháin freastail; buidéil fuisce:

(c) The second noun is not lenited if it is in the genitive plural, e.g. imill bóithre; cnuasaigh dánta:

(d) The second noun is not lenited if it is (i) a person, (ii) an animal, (iii) a living being, or (iv) part of a person, animal or living being:

(i) duáin cailín; buidéil páiste:

(ii) bréagáin madra; sciatháin circe:

(iii) crainn beithe; peitil blátha:

(iv) ailt méire; matáin coise:

(e) The second noun is not lenited if the first noun is part of the second, e.g. cláir báid; méarchláir pianó:

(f) The second noun is not lenited if it is in the genitive and qualified by an adjective or another noun, e.g. cláir dioplóma iarchéime; cláir deice báid:

Exception: when beirt is the second noun, e.g. gluaisteáin bheirt pheileadóirí.

Note that, subordinate to the exceptions in (a) to (f) above, any noun subject to a plural noun ending in a slender consonant is lenited, e.g. comórtais idir-ollscoile chadhcála agus bhoghdóireachta; páipéir bhainc agus pharlaiminte; limistéir pleanála teanga Ghaeltachta. If there is a series of nouns listed before another, however, the initial mutation accompanying the final noun in the list is the one that is applied to the noun or nouns subject to it, e.g. treoracha nó leabhair ghramadaí; leabhair nó treoracha gramadaí.

10.2.9 After Nouns in the Genitive

Indefinite nouns subject to a noun in the genitive are not lenited, e.g. bord údaráis crediúnúcháin; síniú an choinbhinsiúin cóipchirt; suíomh an chruinnithe mullaigh; bord coláiste gairmoideachais; trasna na sráide cathrach:

10.2.10 Definite Nouns after Other Nouns

Definite nouns in the genitive are lenited after other nouns, e.g. Cuan Bhaile Átha Cliath; foireann Dhoire; muintir Sheáin; oibrithe Bhéal Feirste; mac fhear an tábhairne; obair bhean an tí.

Note that definite nouns are lenited even when d, t, or s follows d, n, t, l, or s, e.g. foireann Dhoire; riail Shasana; doras Theach an Phiarsaigh; luas thraein an iarthair:

No lenition is applied:

(a) to the following nouns:

(i) Dé (Dia in the genitive), e.g. lámh Dé; trócaire Dé:

(ii) San or names following it, e.g. Ord San Proinsias; Lá San Svaítín; Lá San Seáin:

(iii) Dé in days of the week, e.g. oíche Dé Máirt; tráthnóna Dé Céadaoin:

(b) to definite nouns following these nouns:

(i) Féile in the genitive, e.g. Lá Fhéile Pádraig; Samhradh beag na Féile Michíl:

(ii) Naomh, e.g. cuimhneachán Naomh Peadar; Naomh Pól:

(c) to a verbal noun followed by a definite noun, e.g. madra cosanta na monarcha; bean fuascailte na ceiste; beach cealgtha an pháiste; innill buailte an arbhair; seachtain bailithe na rátaí (see 3.3.1(a)).

10.2.11 In Surnames

Nouns following Mhic, Mhig, Ní, Nic, Uí in surnames are lenited, e.g. Bean Mháirtín Uí Bhroin; Isibéal Nig Fhloinn; Siobhán Ní Chonchúir; Úna Nic Shuibhne; and after Mac (Mag) in certain surnames, e.g. Mac Pháidín; Mag Fhinn:

Note that c and g are not lenited following Mhic or Nic, e.g. teach Sheáin Mhic Cárthaigh:

10.2.12 In Compound Words

The second word in a compound word is lenited, e.g. dea-cháil, deargbhuile, rósghairdín, sárdhuine, except when d, n, t, l, or s occur next to each other, e.g. antráth, catsúil, clostrácht, galltrumpa, ilsiolla, leasdeartháir, seansaighdiúir.

Note: The second noun in a compound word is not lenited after an- (the emphatic particle) when d, t, or s follow it, e.g. An-duine is ea é; Bhí an-dea-aimsir ann an samhradh sin; An drochrud a bhí sa bhean sin (see 2.1.7).

10.2.13 After the Copula

A noun following the copula in the indicative mood, past or imperfect tense or in the conditional mood, e.g. Ba dhuine mór é; Ar shagart é?; Níor dhochtúir é; Nár cheoltóir maith é; Is dóigh leis gur ghadaí a bhí ann; Dúirt sí gurbh fhiú labhairt léi; Deir sé nár dhochar é; cér chás é (ach); dá mba chailín í; fear dar shloinne Ó Murchú; má ba bhithiúnach é; murar bhréag é (see Chapter 7):

10.3 Lenition of Adjectives

Adjectives are lenited in the following instances.

10.3.1 After Nouns

The first consonant of a qualifying adjective is lenited:

(a) after a noun in the nominative, dative or vocative feminine singular, e.g. bean mhór; don bhean mhór; a bhean mhór:

Note that multi-word adjectival phrases are not lenited, e.g. athnuachan saor in aisce; bean mór le rá; tuarascáil cothrom le dáta (see 4.3.8).

(b) after a noun in the genitive or vocative masculine singular, e.g. mac fir mhóir; a fhir mhóir:

(c) after a noun in the nominative or dative plural, if it ends in a slender consonant, e.g. fir mhóra; do na fir mhóra (exception: caora in the nominative plural, e.g. caoirigh beaga bána móra, etc.):

Note that parentheses break the grammatical link, e.g. gnóthais (beag nó mór).

(d) in the case of numbers:

(i) after nouns preceded by dá or dhá, e.g. dhá bhó bhána; luach an dá bhó bhána; an dá leabhar déag mhóra; dhá dhuinneog mhóra is tríocha; dhá cheann mhóra is ceathracha:

(ii) after singular nouns preceded by a number from trí to deich, e.g. trí (ceithre, cúig, sé) bhád mhóra; seacht (ocht naoi, deich) gcapall mhóra; trí (ceithre, cúig, sé) fhuinneog déag mhóra; seacht (ocht, naoi, deich) mbád déag mhóra; ocht gcéad nócha is naoi mbád bheaga; lucht na dtrí (gceithre, etc.) bhád mhóra; ainmneacha na seacht (n-ocht, etc.) gcapall mhóra:

Note that, if the Simplified System is used above twenty (see 9.3.10 – 9.3.12), lenition is only applied to adjectives following a feminine noun, e.g. fiche a trí capall mór; 45 fuinneog mhór.

(iii) after the plural form cinn when preceded by a number from trí to deich, e.g. trí cinn dhubha; cúig cinn mhóra is seasca:

(e) in the dative masculine singular, if the Lenition System is in use (see 1.7).

10.3.2 Before Nouns

When an adjective comes before a noun:

(a) the adjective is lenited following a simple preposition, following a simple preposition and the article and following a possessive adjective in the same manner that a noun is lenited, e.g. ar thrí euro; don cheathrú bean; mo shéú hubh (see 9.5.1):

(b) ordinal numbers in the genitive are lenited in the same way as a masculine noun, e.g. doras an cheathrú seomra, but f is not lenited, e.g. i dtrátha an fichiú lá (see 9.5.4(d)):

Note that no lenition is applied:

(i) to ordinal numbers in the nominative, except céad (see 9.5.1(b)), e.g. an tríú duine; an cúigiú bean; but an chéad áit; na chéad chéimeanna:

(ii) to cibé, gach or pé:

(iii) to the possessive adjectives mo and do, e.g. ar mo mhála; faoi do chara:

10.3.3 To dhá and dháréag

The adjectives dhá and dháréag are lenited, e.g. mo dhá bhróg; bhí dháréag i láthair, except after the singular article (an, don, sa, etc.), aon and chéad, e.g. an dá áit; gach aon dá uair an chloig; an chéad dá bhliain; an Dáréag Aspal; gach aon dáréag acu; an chéad dáréag a cháiligh; Cogadh an Dá Aodh.

10.3.4 To déag and fichead

The word déag is lenited after dó and after nouns ending in a vowel, e.g. trí bhó dhéag; cúig lá dhéag; except in ordinal numbers (see 9.5.2(e)). The word fichead is lenited after nouns having a slender plural, e.g. trí cinn fhichead.

10.3.5 In Compound Words

The second word in a compound word is lenited, e.g. beagmhaith, fíordheas, except when d, t, or s comes after d, n, t, l or s, e.g. antrom, bándearg, caolsrónach, casdubh, fadsaolach, ildánach, ilteangach.

10.3.6 After the Copula

Adjectives are lenited after the copula in the indicative mood, past and imperfect tense, and the conditional mood, e.g. Ba dheas uait é; Ar mhaith leat é?; Níor bheag an gaisce é; Nár dhona an lá é?; B’fhéidir nár chneasta uaim é; Dá mba mhaith leat teacht, bheadh fáilte romhat; má ba shaibhir an fear é (see Chapter 7).

10.4 Lenition of Verbs

10.4.1 Lenition of Independent Verbs

Independent verbs are lenited:

(a) in the indicative mood, past and imperfect tense, and the conditional mood, e.g. mhol mé (mhol tú, etc.), mholainn (mholtá, etc.), mholfainn (mholfá, etc.), mholtaí, mholfaí:

(b) after a, direct relative, and after the conjunctions má and ó:

(c) in a declarative subordinate clause that acts as a subject for the copula in forms such as Is ann a chonaic mé é; Is leis a bheidh mé:

However, note:

(i) Outside of certain irregular verbs – bhíothas, chonacthas, chualathas, chuathas, thángthas – the autonomous verb is not lenited in the past tense, e.g. Buaileadh go dona iad; an geall a briseadh:

(ii) The verb abair is not lenited in any instance:

10.4.2 Lenition of Dependent Verbs

Dependent verbs are lenited after the conjunctions and verbal particles ar, cár, dár, gur, murar, nár, ní, níor, sular:

However, note:

(a) the dependent form of the verb faigh is eclipsed in the past tense, the future tense and the conditional mood after the verbal particle ní, e.g. Ní bhfuair tú ansin iad; Ní bhfaighinn aon chabhair uathu (see 10.8.2(b)).

(b) the verb abair is not lenited in any instance, e.g. Ní déarfadh aon duine gur theip ort.

10.5 Lenition of Pronouns

10.5.1 After the Preposition ó

The demonstrative pronoun sin is lenited after the preposition ó in the phrase ó shin (‘in the direction of’).

10.5.2 After Prepositions

The interrogative pronouns cá, cad, cé, etc. are not lenited:

Eclipsis

The eclipsable consonants are b, c, d, f, g, p, and t. Where eclipsis is applied to a consonant, n- is added to a vowel, except in the dative case after the article or the article combined with a preposition, e.g. ar an uisce, faoin ábhar; and in the case of i (see 10.6.4). A hyphen is added between the eclipsis n and the vowel, e.g. líon na n-ospidéal; except when the noun is a capital letter, e.g. meon na nAlbanach.

10.6 Eclipsis of Nouns

Eclipsis is applied to nouns in the following instances.

10.6.1 After the Article

Nouns are eclipsed after the article:

(a) in the dative singular, masculine and feminine, in some instances when a preposition accompanies the article, e.g. ar an gcapall; faoin bhfoirgneamh (see 1.4):

Note that there is always eclipsis in the phrases mar an gcéanna and um an dtaca.

(b) in the genitive plural, masculine and feminine, e.g. seolta na mbád beag; scoil na gcailíní óga:

10.6.2 After Plural Possessive Adjectives

Eclipsis is applied to to nouns after the plural possessive adjectives, e.g. ár n-athair; bhur bpáistí; a ngluaisteáin:

Note that eclipsis follows dhá if preceded by a plural possessive adjective, e.g. ár dhá gcapall; ár dhá gcúigiú cuid; bhur dhá dteach; a dhá mbó (see 8.3.3).

10.6.3 After Certain Numbers

Eclipsis is applied to nouns following the cardinal numbers seacht to deich, e.g. seacht ndícheall; ocht gcinn; naoi mbliana; deich n-eachtra (see 9.3.1(i)):

No initial mutation is applied to the nouns euro and cent, e.g. seacht euro; naoi euro; deich cent.

Note:

(a) that it is the initial mutation pertaining to the final number in a series that is applied to the word or words subject to it, e.g. sé nó seacht mbád;

(b) if the Simplified System is used above twenty (see 9.3.10 – 9.3.12), no lenition is applied to the noun, e.g. fiche a seacht capall; 49 fuinneog.

10.6.4 After Certain Simple Prepositions

Eclipsis is applied to nouns following these simple prepositions:

(a) i, e.g. i mbaile; i bpáirc; i mBaile an Fheirtéaraigh:

Before a noun starting with a vowel, this is written in, e.g. in eaglais; in Albain; in Áth Dara; in Éirinn; in aon chás; and in the following instances:

(i) before bhur, dhá and go leor, e.g. an áit a bhfuil sibh in bhur gcónaí; in dhá áit; in go leor cásanna:

(ii) before the title of a book, journal or film, etc. and before abbreviations of titles of organisations, unions, scemes, etc., e.g. in An tOileánach; alt in Comhar; in AE; in CAE; in FSS (see 3.2.2B):

(iii) before loaned placenames that are not Gaelicised, e.g. in Birmingham; in Barcelona, in Köln (but i Londain, i mBostún):

(iv) before years when written in figures, e.g. in 1998; in 2017.

(b) ar in a handful of forms, e.g. ar gcúl; ar ndóigh; and after the preposition go (when not meaning go dtí), e.g. go bhfios dom; go gcuimhin liom:

10.6.5 After cá

Eclipsis is applied to the noun in the established phrase cá bhfios:

10.7 Eclipsis of Adjectives

Eclipsis is applied to adjectives that come before a noun in the same way as it is applied to nouns (see 10.6). That is, an adjective following the article in the dative singular in certain instances, e.g. ar an gceathrú hurlár; in the genitive plural, e.g. i rith na gcúig oíche; after plural possessive adjectives, e.g. ár gcéad mhac; and after the preposition i, e.g. i ngach leabhar.

Note that no lenition is applied to:

(a) cibé, pé or the possessive adjective do, e.g. i cibé foirm; i pé páipéar; i do mhála:

(b) an adjective following a noun, e.g. cumann na bhfear óg; seolta na mbád dubh.

10.8 Eclipsis of Verbs

Verbs are lenited in the following instances.

10.8.1 In Relative Subordinate Clauses

Eclipsis is applied to the verb in a relative subordinate clause after:

(a) a, indirect relative, and nach, e.g. an bainne nach n-óltar; an bhean a dtagann a páistí ar scoil; an duine a gcáintear é; an duine nach gcáintear é; an fear nach gcuirtear cúram air:

(b) a preposition combined with a, indirect relative (see 11.6.1(c)), e.g. an tAcht dá (from do + a) dtagraítear; an Bille lena (from le + a) ndéantar leasú:

(c) a (with the meaning an méid a) and dá (from de/do + a), e.g. d’ólfadh sé a bhfeicfeadh sé; gach aon duine dá dtagann ann; gach áit dá ndéantar tagairt:

10.8.2 After Conjunctions and Certain Particles

Eclipsis is applied to a noun after the conjunctions and verbal particles:

(a) an, cá, dá (conditional), go, mura, nach, sula:

However no n- is placed before a vowel after an, e.g. An ólann tú tae?; An itheann tú feoil?; An athróidh tú é?:

(b) ní, in the case of the dependent form of the verb faigh in the past tense, the future tense and the conditional mood, e.g. ní bhfuair mé (tú, etc.), ní bhfaighidh mé (tú, etc.), ní bhfaighinn (bhfaighfeá, etc.):

t before Vowels or s

A hyphen is placed between the prefixed letter t and a vowel, e.g. an t-ospidéal; except when the vowel is a capital letter, e.g. an tAlbanach. No hyphen is added between t and s, eg. an tsatailít; an tSeapáin.

10.9 t Before Vowels After the Article

10.9.1 A t- is added before a vowel after the article:

(a) in the nominative singular, before a masculine noun if it starts with a vowel, e.g. an t-asal; an t-eitleán:

Note that t- is not placed before euro, iomad or oiread, e.g. an euro, an iomad, an oiread.

(b) in the nominative singular, before aon, aonú, ochtó, ochtódú, ochtú, e.g. an t-aon bhean déag; an t-aonú háit déag; an t-ochtó bliain; an t-ochtódú huair:

10.10 t Before s After the Article

10.10.1 A t is placed before s after the article if it is followed by a vowel or l, n or r in certain instances after the article according to Chapter 1, e.g. an tslat; an tsnaidhm; an tsreang; ar an tsráid; faoin tsinsearacht; deireadh an tséasúir; eochair an tsiopadóra; cótaí an tseachtair.

10.10.2 t is not placed before s:

(a) in numbers, e.g. deireadh an seachtú lá; agallamh an seascadú duine; except personal numbers in the genitive, e.g. ainmneacha an tseisir; torthaí an tseisear scoláirí:

(b) after aon and the ordinal number céad, e.g. aon salann; aon seanmóir; an chéad sagart:

h Before Vowels

No hyphen is added between a prefixed h and a vowel, e.g. le háthas; go hÉirinn; na húlla. An h is placed before a vowel in the following cases.

10.11 h Before Vowels – Nouns

10.11.1 After the Article na

An h is added before a noun starting with a vowel after the article na:

(a) in the genitive feminine singular, e.g. ainm na háite; lár na heitilte.

(b) in the nominative plural and dative plural, e.g. na hainmneacha; sna hionaid sin:

10.11.2 After Certain Numbers

(a) An h is placed before a noun starting with a vowel after ordinal numbers, e.g. an dara (tríú, etc.) heochair; except céad, e.g. sa chéad áit; an chéad obráid.

(b) An h is placed before uaire after trí, ceithre, cúig, sé, e.g. trí (ceithre, cúig, sé) huaire (see 9.3.2(c)).

Note that the special plural form of the noun uair is not used when the unit of 60 minutes is the meaning, e.g. Thóg sé trí uair an chloig orm an obair a chríochnú.

10.11.3 After the Prepositions le and go

An h is placed before a noun starting with a vowel after the preposition le and go (with the meaning go dtí), e.g. ó mhaidin go hoíche; le hintinn mhaith; le hÁine; go hAlasca.

10.11.4 After Interrogative Pronouns

An h is placed before a noun starting with a vowel after the interrogative pronoun cá, e.g. cá hiontas?; cá háit?

10.11.5 In Surnames

An h is added before a noun starting with a vowel after Ó in surnames, e.g. Seán Ó hÓgáin; do Chathal Ó hAodha.

10.11.6 After Dé

An h is placed before the vowel after Dé in Dé hAoine.

10.11.7 After the Possessive Adjective a

An h is added to a noun starting with a vowel after a, possessive adjective, in the third person feminine singular, e.g. a hathair.

10.11.8 After ní

An h is added before a vowel after ní (the negative form of the present tense of the copula (see 7.2.5)):

(a) to the nouns áibhéil, ionadh, iontas and ualach:

(b) to the nouns in the prepositional copular phrases acmhainn do; áil le; aitheanta do; aithnid do; éadáil le; ealaín do; éigean do; and eol do:

(c) to nouns in a handful of proverbs:

Note that h is not placed before a noun after ní outside of the cases given above, e.g. Ní amadán é; Ní Eoin is ainm dom; Ní eolas oideachas.

10.12 h Before Vowels – Adjectives and Adverbs

10.12.1 After chomh, go, le

An h is added to an adjective or adverb starting with a vowel after chomh, go, and le, e.g. chomh hard le haon chapall; Tá sé go hálainn.

10.12.2 After ní

An h is added before a vowel after ní (the negative form of the present tense of the copula (see Chapter 7)):

(a) to the adjectives amháin, aon, ionann and iondúil, and to the adverbs amhlaidh and annamh:

(b) to the adjective in the prepositional copular phrases eagal do/le and oircheas do:

10.12.3 After a and na

An h is added before a vowel after a and na in numbers, e.g. ceacht a haon; na hocht gcinn.

10.13 h Before Vowels – Pronouns

10.13.1 After cé and ní

An h is added before a vowel after cé and ní to the personal pronouns é, í, ea and iad, e.g. ní hé; ní hí; ní hea; ní hiad; cé hé?; cé hí?; cé hiad?

10.13.2 After ní

An h is added before a vowel after ní to the demonstrative pronouns éard, eo, in and iúd, e.g. ní héard; ní heo; ní hin; ní hiúd.

10.13.3 After le

An h is added before a vowel after le to the personal pronouns é, í and iad, e.g. le hé; le hí; le hiad.

10.14 h Before Vowels – Verbs

10.14.1 After ná

An h is added before a vowel after ná in the imperative mood, e.g. ná himigh.

d’ Before Vowels or fh – Verbs

Where lenition would apply to a consonant in the past and imperfect tense, indicative mood, and the conditional mood, d’ is added before a vowel or fh-, e.g. d’fhágamar; d’fhanadh sibh; d’fhreagróinn; d’imeoinn; d’ithinn; d’ól sé; an té a d’imigh; d’aithneofaí í; má d’fhág sé; má d’fheiceadh sé; má d’imríomar.

10.16 Summary of Initial Mutations

For ease of reference, a summary is given here of the cases in which lenition is applied to nouns, adjectives, verbs and pronouns. Full descriptions are given under the cross-references in the left column.

For ease of reference, a summary is given below of the cases in which eclipsis is applied to nouns, adjectives and verbs.

For ease of reference, a summary is given below of the cases in which t is placed before a vowel at the start of nouns and adjectives.

For ease of reference, a summary is given below of the cases in which t is placed before s at the start of a noun.

For ease of reference, a summary is given below of the cases in which h is placed before a vowel at the start of a noun, adjective, adverb, pronoun or verb.

For ease of reference, a summary is given below of the cases in which d’ is placed before a vowel or fh- at the start of a verb.