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The Mysteries of Irish Spelling

Moonlight over the River Shannon, Ireland.
Moonlight over the River Shannon, Ireland.

I once knew a fellow who was a huge advocate of a simplified, phonetic (from an English-speaker’s standpoint) spelling system for Irish.

But Irish isn’t English, and using an English spelling system to represent the sounds of the language (some of which don’t even exist in English: See The Sounds of Irish Gaelic Part 1 and The Sounds of Irish Gaelic Part 2) really doesn’t make a lot of sense.

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(Not to mention that it’s more than a bit arrogant. Why should English be the phonetic standard by which other languages are rendered? But I digress).

Not as difficult as it might seem

Initial impressions aside, Irish spelling really isn’t all that complicated, once you understand the “why” of it. What initially may seem like an incomprehensible cluster of letters becomes comprehensible pretty quickly once you know what’s going on.

All those letters!

You may be surprised to learn that Irish underwent a spelling reform in the 1950s, which removed a lot of silent letters that didn’t serve some other purpose (what those purposes may be we’ll talk about below).

In order to accommodate typewriters (and today, keyboards), Irish also lost a diacritic mark, replacing it with letter that is common in English, but less so in Irish. We’ll talk about that as well.

The result of this reform is that Irish actually has considerably fewer unnecessary letters (by a lot!) than English does.

Let’s start with the consonants

Consonant combinations, particulary at the beginning of a word, can be especially confusing to new learners, primarily due to a grammatical feature of the language known as “initial mutation.” (Bitesize subscribers can explore this concept in more depth, with audio, in Lesson: Initial Mutations).

Initial mutation, a change to the sound of the beginning of a word, is a feature of most Celtic languages. It serves to indicate the word’s relationship to other words in the sentence, as well as to make words easier to pronounce in context.

Irish has two kinds of initial mutation: eclipsis and lenition.

Eclipsis (úrú)


Eclipsis happens when the sound of an initial consonant is covered up (“eclipsed”) by another consonant. This can happen in a variety of grammatical situations, but is probably most commonly encountered after the preposition i (in).

In some languages, the old consonant is completely replaced, in writing, by the new consonant. In Irish, however, the new consonant is written in front of the old one. So, for example:

I (in: pronounced “ih”) + bád (a boat: pronounced “bahd”) becomes i mbád (in a boat: pronounced “ih mahd”).

The nice thing about doing it this way, rather than simply writing i mád, is it makes such words much easier to look up in a dictionary. Simply remove the “m” and bád will be very easy to find! For more on this, see our post on “Finding Words in an Irish-English Dictionary.”

To make things even simpler, consonants are always eclipsed by the same letters. For example, if eclipsis is called for, bád will always become mbád, never something like dbád or pbád.

Here’s how it breaks down:

B becomes mB

C becomes gC

D becomes nD

F becomes bhF

G becomes nG

P becomes bP

T becomes dT

The other consonants can’t be eclipsed.

Something like eclipsis


There is another letter combination that looks and acts like eclipsis but is technically something else because it’s used in different grammatical circumstances: tS

For pronunciation purposes, however, it behaves just like eclipsis in that only the “t” is pronounced.

Lenition (séimhiú)


Lenition refers to the softening of a consonant’s sound (the Irish word for it, séimhiú, pronounced “SHAY-voo,” literally means “softening/gentling”). We talk about this a bit in “The Sounds of Irish Gaelic Part 1,” and Bitesize subscribers will encounter it quite a lot in our various conversation lessons.

In contemporary written Irish, this is indicated by writing the letter “h” after the consonant to be softened. Pre-spelling reform, it was indicated by writing a dot over the letter, and you’ll still see that from time to time on signboards and such. (This is the eliminated diacritic mark I mentioned above.)

H was chosen, by the way, because it’s not a common letter in Irish, appearing (before this change) mainly in loan words.

Lenition can appear in a variety of places, including in the middle or at the end of words. One of the most common places to encounter it at the beginning of a word is after the possessive adjective mo (“my”). For example:

Mo (my: pronounced “muh”) + bád (a boat: pronounced “bahd”) becomes mo bhád (my boat: pronounced “muh wahd”).

On to the vowels

My husband like to make jokes about what he calls “The Great Vowel Wars.” He claims that Ireland and Wales fought over which language needed vowels the most. Ireland won, and now liberally sprinkles vowels everywhere, whereas poor old Wales has to make do with Y and W.

(It’s fun having a hubby with a sense of humor!)

Some Irish words may appear to have more vowels than are strictly necessary, but here’s a secret: A lot of those vowels are only there to satisfy an important spelling rule.

Caol le caol agus leathan le leathan


One of the first spelling rules any Irish learner learns is “caol le caol agus leathan le leathan” (“slender with slender and broad with broad”).

Irish vowels fall into two classifications: slender and broad. The slender vowels are I and E. The broad vowels are A, O, and U.

What “slender with slender and broad with broad” means is, if you have a slender vowel on one side of a consonant group, you must have a slender vowel on the other side as well. The same, of course, is true of broad vowels.

The reason this rule is important is the pronunciation of a consonant changes depending on the vowels next to it. For this reason, we also refer to “slender and broad consonants.” For example, an R with an O on one side and a U on the other side would be called “broad R,” and pronounced accordingly.

(For more on how this works, you can check out “The Sounds of Irish Gaelic – Part 1” and “The Sounds of Irish Gaelic – Part 2.” Bitesize subscribers will also want to look at Lesson: Spelling Rule.)

What this comes down to in terms of spelling is that, in groups of more than two vowels, typically the one closest to the consonants in the middle or at the end of a word is there to satisfy this spelling rule and to tell you how to pronounce the consonant.

Lots of letters, sure

It’s true that Irish appears, at first glance, to use a lot more letters than is strictly necessary. When you understand why those extra letters are there, though, and how they function, the whole thing is a lot less daunting.

Unlike English, Irish doesn’t tend to have many vestigial letters (unpronounced letters left over from older pronunciations, such as the “k” in the English “knife”). There are a few, but generally speaking, all the letters in a given word serve a purpose.

Once you’ve had a bit of experience with the spelling system, you’ll be surprised at just how intuitive much of it is.

Further demystification at your fingertips

For more information on how Irish spelling works have a look at our Irish Pronunciation Cheat Sheets  : A valuable tool for those who are studying the Irish language, as well as for those who simply want to get a better idea of what those strange-seeming letter combinations actually sound like.

Did you find this post helpful?

Did you know all this about Irish spelling? Let us know your thoughts below.

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20 thoughts on “The Mysteries of Irish Spelling”

  1. Ah this is awesome! Now I see the vowel spellings have purpose!!!!!!! I wasn’t sure until reading this. For people frustrated by this, English is a more frustrating language to spell than Irish, much less logic to latch onto. You just grew up with English so you find it easy. My Japanese friend who is learning English is suffering with the spelling!

  2. Sorry,but your explanation was beyond me,if these letters are silent why write them down? I heard a Welsh woman living in Connemara saying that very little Irish is read there,could this be part of the reason? I know that English spelling is eccentric,to say the least but that is a very dominant culture that does not face the obstacles weaker cultures have to contend with.

    1. Arthur, a chara
      If you would like to find out more about the wonders of spelling and pronunciation in the Irish language, we have a great course called ‘Crack Irish Pronunciation’ available through our memberships. You can find out more about it here.

    2. I was totally shocked to find my name in Irish been spelt as if it were English.. Rather than change a language to suite English speakers. It should have been left alone.

  3. ‘ Did you find this helpful’. I’m sorry,but no. Incidentally English is not my first language and I do not know how may vowels you have in Irish, but in Welsh we have a,e,i,o,u,w & y. Best of luck with your efforts’

    1. I was just wondering why my surname is spelt more or less phonetically in Welsh,or Owain in a more correct form still said much as it is spelt,but in Irish it is spelt Eoghan,and I used to know a young girl called Siobhan no trace of a B in the pronounciation.

      1. Arthur, a chara
        Although Welsh and Irish are both Celtic languages, they are quite different and fall into separate categories within Celtic languages.
        There is something called ‘lenition’ which is the softening or silencing of letters with the use of a ‘h’. In the name ‘Siobhán’, the ‘b’ is softened by the ‘h’ causing it to be pronounced like ‘shuh-wan’ or ‘shi-vawn’. The ‘v’ sound is the more common pronunciation.
        So in short, the ‘b’ in siobhán isn’t pronounced due to the ‘h’ beside it! Apply that to the ‘g’ in ‘Eoghan’, it is softened and basically disappears due to the lenition or ‘h’.

        I hope this helps clear things up 🙂
        Le beannacht

  4. City of Canada Bay Men Shed

    Very interesting and useful.
    Last time I did Irish Reading and Writing was in year 2 secondary when the boulties (dots over B etc) were in so I have found it difficult to adjust to the h which seems to be used instead.

  5. i remember the desk at which I was sitting when our National School Teacher tole me that I must not use the Seimiú (I don’t want to use the h diacritic there) any longer. I am greatly saddened by this as I feel that a very visual characteristic of written Irish was lost and with it, a piece of our national heritage.
    I am also shocked to see the english letter V used a lot now – Votáil, Coronavireas, etc.

  6. Very interesting. I am learning Scots Gaelic which doesn’t have eclipsis. I’d been wondering how Irish pronounced the extra letters at the start of their words! It feels like Irish has less silent letters overall. But the main thing is that both languages have consistency of pronunciation – English is much harder by comparison!

    1. i remember the desk at which I was sitting when our National School Teacher tole me that I must not use the Seimiú (I don’t want to use the h diacritic there) any longer. I am greatly saddened by this as I feel that a very visual characteristic of written Irish was lost and with it, a piece of our national heritage.
      I am also shocked to see the english letter V used a lot now – Votáil, Coronavireas, etc.

  7. Noah C. Johnson

    from a language learner who has been learning irish for about 5 months, i am really starting to get irish spelling, it is far from phonetic by english standards, but english is only 19% phonetic by english standards (based upon the percentage of words spelled exactly as they sound), so no language is phonetic by the standards of english. i am starting to get good enough at irish spelling (even if not quite the vocabulary and grammer) that i can typically geuss how a word i have seen in writing in irish, but have not heard in speech yet is pronounced, just as well, if not better then in english. although i blame the horrific inconsistencies and senselessness of english spelling for that.

    1. Hi Alexander,

      I’m not familiar with this name, it doesn’t look like an Irish name or sound like one. Where did you hear or find the name? If I heard it I might be able to help.

      Le beannacht,