The following article describes the Irish spelling system.

Irish Spelling

by Christoph Wendler


Literacy has a long tradition in Irish. There seems to have been a standardised spelling for Irish as early as the 7th century, during the Old Irish period. It was the result of a long process of adapting Roman letters to the Irish sound system. By then, Roman letters had replaced Ogham[1], the first writing system for Irish that was used between the 3rd and the 6th century.

Irish even had its own variety of Roman letters. During the Middle Ages a script called Gaelic was developed. It gives texts written in Irish a distinctive look, and was commonly used until the early 20th century, when it was replaced by ordinary Roman letters. You have probably seen inscriptions and signs in the old Gaelic script, like for example:

céad míle fáilte (céad míle fáilte)

The old Gaelic script was replaced, because it was cheaper to print books and newspapers in ordinary Roman letters. Today practically everything published in Irish is printed in Roman letters, and the Caighdeán Oifigiúil (CO), the official standard for written Irish, uses Roman letters as well.

Although the existence of an official standard suggests that there is some sort of "Standard Irish", there are no actual speakers of "Standard Irish". Today Irish continues to be spoken as an everyday language only in small areas known as Gaeltacht ("Irish speaking area"), mainly along the western seaboard, with small pockets in Cork and Waterford. This means that native speakers of Irish invariably speak a local variety or dialect. These dialects can be divided into three main groups: Ulster, Connaught and Munster. There are considerable differences between these dialects in both pronunciation and grammar. The Caighdeán Oifigiúil is a compromise that aims to integrate all three major dialects. This means that a word written in the standard spelling will be pronounced differently by speakers of different dialects. However, these differences are more often than not predictable and do not prevent us from having a standardised spelling system for Irish. In fact, Irish spelling is quite consistent[2], and once you understand the systematic relationship between the spelling and the Irish sound system, you will be able to master it.

In the remainder of this document we will explain the Irish spelling system and how it relates to the Irish sound system. After reading this you will have a better understanding of why Irish words are spelled the way they are, and you'll be able to read and write in Irish with more confidence. So let's dive right in!

1. The Alphabet

The Irish alphabet is based on Latin.[3] It consists of only 18 fundamental letters:

a b c d e f g h i l m n o p r s t u

There are six other letters that may appear in loan words, foreign place names and the like:

j q v w x z

2. The Vowels

2.1 Simple vowels (monophthongs)

Irish has five letters for vowels a, e, i, o, u which can be short or long. If a vowel is long, the length mark síneadh fada, often just referred to as "fada" (fada means "long"), is used like so:

Á, á; É, é; Í, í; Ó, ó; Ú, ú

All other letters are consonants.

2.2 Diphthongs

Apart from simple vowels, Irish also has sounds that consist of two vowels, called diphthongs. There are various ways to express these sounds in spelling. The diphthongs that consist of vowel letters only are:

ia, ua

Other diphthongs are spelled with a combination of vowels and consonants and will be dealt with later. Let's first have a look at the consonants.

3. The Consonant System: "broad" and "slender"

This section is key to understanding Irish spelling. You should read it carefully. It deals with concepts you might not be familiar with, if you are not a native speaker of Irish. Listen carefully to the sound examples below to "tune your ears".

Irish has two sets of consonants commonly referred to as "broad" and "slender"[4]. In more exact terms, "slender" means that a consonant is palatalised, i.e. articulated with the tongue raised towards the hard palate (just behind the teeth-ridge), whereas "broad" consonants are said to be velarised, i.e. articulated with the back of the tongue raised against the soft palate or velum (at the back of the mouth). It is important to keep in mind that the difference between "broad" and "slender" changes the meaning of a word. Thus, the words labhair "speak" and leabhair "books" are not the same, because they start with a different sound, with a velarised ("broad") and a palatalised ("slender") "l" respectively. Henceforth, the terms broad / velarised and slender / palatalised will be used interchangeably.

3.1 The use of vowel letters to mark broad and slender consonants

Rather than having a separate letter for each consonant, in Irish spelling, the quality of a consonant is indicated by the surrounding vowel letters. Back vowels such as a, o and u indicate that a consonant is velarised (broad), whereas front vowels like e and i indicate that a consonant is palatalised (slender). This is why the word leabhair is spelled with an e after the l. In fact, the e is not even pronounced, its only function is to indicate the quality of the preceding l, to inform the reader that it is slender. Listen to the following example to hear the difference between the two l's:

Listening example 1 (Connemara Irish)
palatalised (slender) velarised (broad)
leabhair labhair

Both words are pronounced almost identically. The only difference is the l that changes the meaning from "books" (leabhair) to "speak" (labhair). This example shows that not every vowel that is written is actually pronounced. In many cases, a vowel's only function is to tell whether a consonant is slender or broad. Consider the following two words, "be" and buí "yellow":

Listening example 2 (Connemara Irish)
palatalised (slender) velarised (broad)
bí b

The u in buí is not pronounced, i.e. the speaker doesn't say "b-u-í", the only vowel pronounced is the í ("i fada"). However, you can hear that the b in buí sounds different from the one in owing to the u after the b.

One important rule of Irish spelling is that the vowels on either side of a consonant or consonant group must match in terms of broad and slender. If a consonant (group) is slender, it must be surrounded by the vowel letters e, é, i, í. If, on the other hand, a consonant (group) is broad, it must be flanked by a, á, o, ó, u, ú. Consider the following example (slender vowels are red, broad vowels are blue):

palatalised (slender) velarised (broad)
eile "other" cearta "rights"

Note that the vowels on either side match. This rule is called

slender to slender, broad to broad

It would not be correct to write the following:

*eila *cearte

The only exception to this rule are a handful of words that were once written as two words and are now spelled as one word, e.g. anseo "here", ansin "there", ansiúd "over there".

It is important to remember that only short vowel letters are used as explicit markers for broad and slender. Long vowel letters (with the fada) are never used only to mark the quality, they are always pronounced at the same time, regardless of what is next to them. Remember that in the examples above, fíor and buí, the vowel letters that indicated the quality of the adjacent consonants are both short vowel letters, o and u. The í on the other hand is pronounced.

The following table shows to which set of consonants each vowel letter belongs:

Length palatalised (slender) velarised (broad)
short e, i a, o, u
long é, í á, ó, ú

3.2 Combined vowel letters

As a consequence of the rule described in 3.1, vowel letters are combined, when the quality of the consonants within a word vary. In a word like mín "smooth" both consonants (the m to the left and the n to the right) are slender. Thus, it is sufficient to write only the í. However, in many cases broad and slender consonants appear within the same word, as is the case for example in fíor "true", where the f is slender and the r is broad. For this reason an o is written in front of the r, which indicates that the following letter, in this case r, is broad.

This is why you will often see Irish words spelled with two or more vowel letters in one syllable. The following sequence of vowel letters represents the speech sound /uː/: iúi. The i's on the left and on the right are only there to tell the reader that the consonants to the left and to the right are slender as in the word ciúin.

ciúin ⟨iúi⟩

As indicated by the colors, the two i's refer to the consonants next to them, not to the vowel sound. Now look at the word glúin "knee":

glúin ⟨úi⟩

Both the g and the l at the beginning of the word are broad. This is why it is not necessary to insert an e or an i. The n at the end, however, is slender, which is why there is an i. But the vowel pronounced is still /uː/.

This rule is also followed, if a word has more than one syllable, as in the word seachtainí "weeks". Again, the colours show which vowel letter refers to which consonant.


Here is the exact mapping. The vowels are are enclosed between by "⟨" and "⟩":

s ea cht  ai  n í
s'  æ  x  t  ə  n' iː

As can be seen from the transcription, each vowel grapheme represents only one vowel sound: /æ/, /ə/ and /iː/ respectively.

3.3 The vowel graphemes

Vowel letters can have two of the following functions, they can:

  1. describe a vowel sound
  2. describe the quality (broad or slender) of adjacent consonants

This gives rise to various combinations of vowel letters, some of which occur more frequently than others. ⟨ea⟩, ⟨ai⟩, ⟨éa⟩ and ⟨éi⟩, for example, are very frequent, whereas ⟨aoi⟩ and ⟨uío⟩ occur less often. In this context it is more convenient to speak of them as vowel graphemes[5]. In Irish spelling there is a finite set of vowel graphemes that cover all possible combinations of consonants and vowels. The following tables give you an overview of the vowel graphemes and what vowel sounds they stand for.

3.3.1 Monophthongs

Short Vowel Graphemes
Grapheme Stressed Unstressed Example Transcription
One letter
a /a/ /ə/ fan /fan/
e /e/ /ə/ te /t'e/
i /i/ /ə/ fir /f'ir'/
o /o/ /ə/ poc /pok/
u /u/ /ə/ pluc /pluk/
Two letters
ai /a/ /ə/ saint /san't'/
ei /e/ /ə/ eile /el'e/
oi /i/, /e/ /ə/ goin /gin'/
ui /i/ /ə/ fuinneog /fiN'oːg/
ea /a/, /æ/ /ə/ teach /t'æx/
io /i/, /u/ /ə/ cion /k'un/
iu /u/ /ə/ fiuch /f'ux/
Three letters
eai /æ/ /ə/ ceaig /k'æg'/
Long Vowel Graphemes (U = Ulster, M = Munster)
Grapheme Stressed Unstressed Example Transcription
One letter
á /ɑː/, /æː/ (U) /ɑː/, /a/ (U) bád /bɑːd/
é /eː/ /eː/, /e/ (U) sé /s'eː/
í /iː/ /iː/, /i/ (U) sí /s'iː/
ó /oː/ /oː/, /o/ (U) lón /loːn/
ú /uː/, /ʊ̈​ː​/ (U) /uː/, /ʊ​̈/ (U) cúng /kuːŋ/
Two letters
ái /ɑː/, /æː/ (U) /ɑː/, /a/ (U) táin /tɑːn'/
éi /eː/ /eː/, /e/ (U) spéir /sp'eːr'/
ói /oː/ /oː/, /o/ (U) tóin /toːn'/
úi /uː/, /ʊ̈​ː​/ (U?) /uː/, /ʊ​̈/ (U) súil /suːl'/
/ɑː/, /æː/ (U) /ɑː/, /a/ (U) mn /mɑːn/
eo /oː/ /oː/, /o/ (U) ceol /k'oːl/
/oː/ /oː/, /o/ (U) s /s'oː/
/uː/, /ʊ̈​ː​/ (U) /uː/, /ʊ​̈/ (U) sl /s'uːl/
éa /eː/ /eː/, /e/ (U) féar /f'eːr/
ío /iː/ /iː/, /i/ (U) díol /d'iːl/
ae /eː/ /eː/, /e/ (U) lae /leː/
ao /iː/, /eː/ (M) /iː/, /eː/ (M) /i/ (U) saol /siːl/, /seːl/
/iː/ /iː/, /i/ (U) c /kiː/
/iː/ /iː/, /i/ (U) cl /kliː/
/iː/ /iː/, /i/ (U) b /biː/
Three letters
eái /ɑː/, /æː/ (U) /ɑː/, /a/ (U) meáin /m'ɑːn'/
aei /eː/ /eː/, /e/ (U) traein /tr'eːn'/
aío /iː/ /iː/, /i/ (U) maíomh /miːw/
aoi /iː/ /iː/, /i/ (U) saoil /siːl/
uío /iː/ /iː/, /i/ (U) buíon /biː(ə)n/
eoi /oː/ /oː/, /o/ (U) meoin /m'oːn'/
iúi /uː/, /ʊ̈​ː​/ (U) /uː/, /ʊ​̈/ (U) siúil /s'uːl'/

3.3.2 Diphthongs

There are two ways of writing diphthongs in Irish. First, purely with vowel graphemes. Second, with a combination of vowels and consonants, typically bh, dh, gh and mh. The latter is far more common and is due to how the language developed over the centuries. The consonant graphemes where indeed pronounced at a certain time, but became vocalised, i.e. they turned into vowels.[6]

Diphthongs 1 (short vowel letters)
Grapheme Stressed Unstressed Example Transcription
Two letters
ia /iːə/ bia /b'iːə/
ua /uːə/ bua /buːə/
Three letters
iai /iːə/ riain /riːən'/
uai /uːə/ uain /uːən'/
Diphthongs 2 (vowel and consonant letters)
Grapheme Stressed Unstressed Example Transcription
abh /au/ /ə(w)/ babhta /bautə/
eabh /au/ /ə(w)/ seabhc /s'auk/
abhai /au/ /ə(w)/ abhainn /auN'/
eabha /au/ /ə(w)/ sreabhann /s'r'auN/
eabhai /au/ /ə(w)/ treabhainn /t'r'auN'/
adh /ai/ /ə/, /əx/, /uː/ fadhb /faib/
eadh /ai/ /ə/, /əx/, /uː/ feadhna /fainə/
aidh /ai/ /ə/, /əx/, /uː/ faidhbe /faib'ə/
adha /ai/ /ə/, /əx/, /uː/ cadhan /kain/
adhai /ai/ /ə/, /əx/, /uː/ cadhain /kain'/
eadhai /ai/ /ə/, /əx/, /uː/ feadhain /f'ain'/
eidh /ai/ /ə/, /əx/, /uː/ feidhm /f'aim'/
agh /ai/ /ə/, /əx/, /uː/ saghdar /saidər/
aigh /ai/ /ə/, /əx/, /uː/ saighdiúr /said'uːr/
agha /ai/ /ə/, /əx/, /uː/ laghad /laid/
aighi /ai/ /ə/, /əx/, /uː/ faighin /fain'/
aighea /ai/ /ə/, /əx/, /uː/ caighean /kain/
ighi /ai/ /ə/, /əx/, /uː/ righin /rain'/
ogh /au/ /ə/, /əx/, /uː/ roghnaíonn /rauniːən/
amh /au/ /ə/, /əw/, /uː/ amhrán /aurɑːn/
eamh /au/ /ə/, /əw/, /uː/ sleamhnach /s'l'aunəx/
amha /au/ /ə/, /əw/, /uː/ tamhan /t'aun/
eamha /au/ /ə/, /əw/, /uː/ deamhan /d'aun/
eamhai /au/ /ə/, /əw/, /uː/ sleamhain /s'l'aun'/
Diphthongs 3 (long vowel letters)
Grapheme Stressed Unstressed Example Transcription
Two letters
/iː ɑː/ sn /s'iːɑːn/
/iː oː/ sg /s'iːoːg/
/uː ɑː/ cn /kuːɑːn/
/uː oː/ sg /suːoːg/
Three letters
iái /iː ɑː/ fiáin /f'iːɑːn'/
iuá /uː ɑː/ Siuán /s'uːɑːn/
uái /uː ɑː/ cuáin /kuːɑːn'/
iói /iː oː/ /oː/ sióige /s'iːoːg'ə/
uói /uː oː/ /oː/ suóige /suːoːg'ə/
Four letters
iuái /uː ɑː/ Siuáin /s'uːɑːn'/

4. Consonants

The native Irish alphabet has less letters than the English alphabet (see 1.). Letters like j and y can appear in a handful of loanwords and mathematical terms. A good example is the word jab "job". In most cases, however, consonant graphemes consist of native letters. Some graphemes can be made up of two and sometimes even three letters, which is mostly due to onset mutations, as in bean > an bhean.

The following table gives an overview of consonant graphemes and their pronunciation.

Consonant Graphemes
Grapheme Example Transcription
One letter
b broad /b/ bád /bɑːd/
slender /b'/ bean /b'æn/
c broad /k/ cad /kad/
slender /k'/ cead /k'æd/
d broad /d/ duit /dit'/
slender /d'/ Dia /d'iːə/
f broad /f/ fad /fad/
slender /f'/ fear /f'ær/
g broad /g/ gúna /guːnə/
slender /g'/ gean /g'æn/
h /h/ hÉireann /heːr'ən/
l broad /L/, /l/ lán /lɑːn/
slender /L'/, /l'/ liosta /l'istə/
m broad /m/ múin /muːn'/
slender /m'/ mise /m'is'ə/
n broad /N/, /n/ nasc /nask/
slender /N'/, /n'/ níos /n'iːs/
p broad /p/ poc /pok/
slender /p'/ pionta /p'intə/
r broad
(always broad
/r/ rua, rí /ruːə/, /riː/
slender /r'/ féidir /f'eːd'ər'/
s broad /s/ suas /suːəs/
slender /s'/ síos /s'iːs/
t broad /t/ tua /tuːə/
slender /t'/ teach /t'æxt/
Two letters
bh broad /w/, /v/ bhán /wɑːn/, /vɑːn/
slender /v'/ bhean /v'æn/
ch broad /x/ chuala /xuːələ/
slender /x'/ Chríost /x'r'iːəst/
dh broad /ɣ/ dhá /ɣɑː/
slender /ɣ'/ dhéag /ɣ'eːg/
fh /∅/ fhad, fhear /ad/, /ær/
gh broad /ɣ/ ghúna /ɣuːnə/
slender /ɣ'/ ghean /ɣ'æn/
mh broad /w/, /v/ mháthair /wɑːhər'/
slender /v'/ mheáin /v'ɑːn/
ph broad /f/ phoc /fok/
slender /f'/ phionta /f'intə/
sh broad /h/ shaint /hæn't'/
slender /h/
(before long vowels)
th /h/ thug
bp broad /b/ bpóca /boːkə/
slender /b'/ bpionta /b'intə/
dt broad /d/ dtonnta /doːntə/
slender /d'/ dteach /d'æx/
gc broad /g/ gcrua /gruːə/
slender /g'/ gcearc /g'ærc/
mb broad /m/ mbás /mɑːs/
slender /m'/ mbean /m'æn/
nd broad /N/, /n/ ndoras /norəs/
slender /N'/, /n'/ ndiaidh /n'iːə(g')/
ng broad /ŋ/ ngúna /ŋuːnə/
slender /ɲ/ ngean /ɲ'æn/
ts broad /t/ tsagairt /tagər't'/
slender /t'/ tsioc /t'uk/
ll broad /L/, /l/ dall /dɑːl/
slender /L'/, /l'/ áille /ɑːl'ə/
rr broad /R/, /r/ carr /kɑːr/
slender /r'/ cairr /kɑːr'/
Three letters
bhf broad /w/, /v/ bhfuil /wil'/
slender /v'/ bhfear /v'ær/

1 More information about Ogham can be found at Wikipedia.

2 Although Irish doesn't have phonetic spelling like Spanish, the spelling rules are quite consistent, by far more consistent than English. Since Irish spelling is a compromise between the three major dialects, it can be called generic in the sense that speakers of each dialect can map the same sequence of letters to their respective sound systems consistently. The word laghad "smallness, fewness", for example, is pronounced /Leid/ in Ulster and /li:əd/ in Munster. These differences in pronunciation are implied. Unlike in English, it is far less common in Irish that the reader doesn't know how to pronounce a given sequence of letters, and it is much easier to memorise the spelling of words based on rules.

There are, of course, exceptions. The sequence bhfaighidh, for example, is pronounced /wiː/ in Ulster Irish. There is no way one can arrive at this pronounciation via Irish spelling rules. Theoretically, it should be spelled bhuí. However, it is a form of the irregular verb faigh "to get" and is spelled bhfaighidh to show its morphological origin. Moreover, the spelling bhfaighidh reflects more closely how the word is pronounced in Munster.

3 In Gaelic script the letters are:

a b c d e f g h i l m n o p r s t u

4 From Irish leathan "broad; wide, extensive" and caol "thin, slender".

5 A grapheme may consist of one or more symbols (letters), like for example ⟨sh⟩ in English. It consists of two letters, yet describes only one speech sound, i.e. /ʃ/ as in sheep. Graphemes are usually written between angular brackets "⟨" and "⟩"

6 This is similar to English night, where the gh became vocalised and turned into the diphthong /aɪ/. In Irish as well as in English the old spelling has been preserved.

[x] uses cookies and we collect data from you when you use any of the services that are provided on this website.

For more information read's Cookie Policy and our Privacy Policy.

I accept