In these tutorials, we are going to learn how to pronounce words in Old Irish. This is a form of Irish / Gaelic which is seen in the earliest manuscripts (c. 600-900 CE / AD). 

It was preceded by Primitive Old Irish and Archaic Old Irish, the form we see in the Ogam inscriptions (c. 300-600). Old Irish was followed by Middle Irish, which was also used in the manuscripts (c. 900-1200). Next was Classical Irish / Gaelic (c. 1200-1600), a form used by poets in both Ireland and Scotland) and finally Modern Irish (c. 1600 to the present). 
If you have studied any modern Irish or Scottish Gaelic, you may see some familiar words or forms, as well as some familiar sound changes (which we will get into later). But there are far more differences than similarities between Old Irish and modern Irish or Scottish Gaelic. 
Interestingly, Modern Irish is not necessarily closer in form to Old Irish than Scottish Gaelic. A lot of sound, grammar and spelling changes happened over the centuries, so in some cases modern Irish is more similar and in other cases Scottish Gaelic is more similar.
The information I am providing is that which I learned at Harvard, where I took all four semesters of Old Irish with Tomás Ó Cathasaigh, a man with a very quick wit, and an amazing storehouse of knowledge. In subsequent years I had mentoring in Old Irish from Professor John Carey and Prof. Neil MacLeod, and have consulted with Dr. Joseph Eska, and Dr. Charlene Eska, among others. 
There are several books that have been published as Old Irish tutorials, and there are some differences between them in terms of rules of pronunciation. Some of this occurs if an author tends to follow the pronunciation rules of the modern languages, which would not be accurate. Tomás was widely known for his excellent knowledge of - and pronunciation of - Old Irish, and his insistence on accurate pronunciation in class, so we will follow what he taught.
Let’s first take a look at vowels. Each vowel has a short version and a long version, which are pronounced differently. If the vowel has no accent mark over it, it is the short version.  If it has an accent mark over it (also known as a ‘fada’), then it is the long version.Also, the following pronunciation rules generally apply to stressed syllables - we will talk about that a little further on. For now, just acquaint yourself with the following:
1) Short a - written: a. 
I have been unable to find an English word that contains this exact sound. It is neither the high/bright ‘a’ sound in the English word cat, nor is it the lower/darker ‘a’ sound in the English word father. You will want to listen to the sound clip to hear the short a sound, which is found in the Old Irish word ‘cath’ meaning ‘battle’
2) Long a - written: á. As in the English word lawn. Found in the Old Irish word ‘bán’ meaning ‘white’
3) Short e - written: e. As in the English word let, and found in the Old Irish word ‘leth’ meaning ‘half, side’
4) Long e - written: é. This is the same vowel sound as in the English word say; found in the Old Irish word ‘én’ meaning ‘bird’
5) Short i - written: i. As in the English word sit; Found in the Old Irish word ‘mil’ meaning ‘honey.’
6) Long i - written: í. This is the vowel sound in the English word see; found in the Old Irish word ‘mí’ meaning ‘month.’
7) Short o - written: o. As in the English word on; found in the Old Irish word ‘lon’ meaning blackbird
8) Long o - written: ó. As in the English word low; found in the Old Irish word ‘bó’ meaning ‘cow’
9) Short u - written: u. As in the English word put; found in the Old Irish word ‘guth’ meaning ‘voice.’
10) Long u - written: ú. This is the sound in the English word ‘too’; found in the Old Irish word ‘tú’ meaning ‘you’ (singular / familiar). 
In Old Irish, most of the time it is the first syllable in a word that is stressed, as in the OIr word ‘mathair’ meaning ‘mother’ - /MA-ther/. However in certain cases, other syllables may be stressed (as in the case of compound verbs like ‘do-beir’ /do - BAYR/
In earlier forms of Irish, unstressed syllables were pronounced according to the guidelines above. But by the time of the Old Irish manuscripts, unstressed vowels are generally pronounced like the ‘e’ sound in ‘the’ (or ‘uh’) 
Sometimes we see combinations of vowels, and these can be a little trickier to parse. One of the most common sounds represented by two vowels is seen in the word ‘táin’ meaning ‘cattle raid.’ 
It can be represented in writing in a number of ways, including áe, ái, óe and ói. This is a sound not found in English. It can best be understood as /ah + ee/ - spoken all in the same syllable. You can hear this in the sound clip.
There are other vowel combinations as well, such as: 
uí seen in ‘druí’ meaning ‘druid’
áu as in ‘áu’ meaning ‘ear’
éu / éo as in ‘béo’ meaning ‘living’
íu as in ‘clíu’ meaning ‘fame’
These follow the same pattern as above, in which the two vowel sounds are pronounced one after the other, but all in the same single syllable. 
In other cases, where we see a broad vowel (A, O, U) followed by a slender vowel (I, E)  it denotes a grammatical change of some kind. In these instances, the broad vowel is still pronounced as above, either long or short... but the palate is then slightly lifted to include a very slight short-e or short-i sound after it, spoken all in one syllable.
For example the name ‘Bran’ is spelled ‘Brain’ when it means ‘of Bran.’ It’s a very subtle sound change, inserting an almost imperceptible slender vowel sound after the first vowel. It also very subtly changes the following consonant sound. You can hear this on the sound clip. 
Now let’s look at consonants. Most are pronounced basically the same as in English when they occur at the start of a word.  However, consonants change sound when they occur in the middle of a word between vowels, or at the end of the word after a vowel.
In those cases:
b is pronounced /v/ as in ‘aball’ meaning ‘apple tree’
 c is pronounced /g/ as in ‘ocus’ meaning ‘and’
d is pronounced /dd/ - which represents the ‘th’ sound in ‘other’. (This is different than written ‘th’ which is pronounced as in ‘think’) This sound occurs in OIr ‘grád’ meaning ‘grade, rank, order’
g is pronounced like a soft gh in the back of the throat, as in the goddess name ‘Bríg’ (earlier form, prior to Brigid etc)

m is pronounced like /v/ but with a bit more emphasis than happens with b. Add a slight vibration from the lower lip up against the upper lip. This is a very subtle difference and for now you may choose to pronounce it like /v/ in these phonological cases.  This is heard in OIr ‘amal’ meaning ‘as, like’

p is pronounced /b/ as in OIr ‘topar’ meaning ‘well’

t is pronounced /d/ as in OIr ‘cét’ meaning ‘first’ (or in some situations, ‘hundred’)

The letters L, N and R are slightly less stressed or emphasized (not a sound change that you should worry about now), and the letters f and s stay the same.
Sometimes, however, when a consonant appears in the middle or end of a word, it will retain its original sound - the sound it takes at the start of the word- depending on how that word was originally spelled or formed in earlier forms of the language. 
Some of this we just have to memorize, but luckily in some cases, when a consonant is not going to change sound in the middle or end of a word, it will be doubled. 
A good example is the word ‘immrama’ (literally a ‘rowing about,’ often translated as ‘journey’). The first M is doubled, so even though it is in the middle of a word it is still pronounced just like an M. However the second M is not doubled, so it will be pronounced like a ‘v’. So the word is pronounced: IMM - rah - vuh. 
Another important thing to note is that when S is followed by a slender vowel (e or i) it becomes an ‘sh’ sound: as in the OIr word ‘sen’ meaning ‘old’: /shen/.

This can also sometimes happen when S is preceded by a slender vowel, as in the word ‘inis’ meaning ‘island’: pronounced /IN - ish/
You will also see the consonant combinations Ch, Th and Ph. 
Ch is pronounced as in ‘loch’ (meaning ‘lake’) or the name of the composer ‘Bach,’ in the back of the throat ( *never* as in ‘choose’)
Th is the ‘th’ sound in ‘think’; seen in the OIr word ‘bith’ meaning ‘world’
Ph is pronounced /f/ as in English. 
[Btw words starting with the letter p are almost invariably loan words from other languages, since Old Irish is a Q-Celtic language].
Finally, sometimes when we see two consonants back to back, there may be a slight ‘uh’ sound inserted between them, as in the Old Irish female names Medb and Sadb (which we will learn next lesson). The sound clip contains an example of this in regards to the Gaelic word ‘tarbh‘ meaning  ‘bull’ (in OIr Tarb ‘bull’ is pronounced /tarb/). More on this in another lesson...
I think this is plenty to read and think about over the next week! 
After this we will look at deity names; followed by important terminology and place names that we encounter in the mythological literature; and finally some beginning grammar that might be useful in your personal practice. 
Many blessings to all! 
Please note: This information is for personal study and practice only.
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Copyright 2018 Sharon Paice MacLeod