Broad vs Slender

Depending on how long you've been doing Gaelic, you have probably come across the "Golden Rule" of Gaelic, caol ri caol is leathann ri leathann - broad with broad and slender with slender. Probably, you'll have also learned that there are vowels which are considered broad and some which are considered slender and that the same distinction applies to consonants.

Back up a moment?

Sure. So what is this broad and slender business really about? Well, the short answer is that e and i, and sounds surrounded by them, are considered slender, and a, u and o, and sounds surrounded by them, are considered broad. For example, in aba [abə], all three letters are broad and the reason for that will be explained, further down, with an examination of how letters contiguous to one another affect one another. In seinn [ʃeiNʲ] on the other hand, all four letters (nn counts as one letter) are slender because they are contiguous to e/i, the slender vowels.

I feel I need some background to this answer...

The long answer is, well, longer. Fundamentally what's happening here is that Gaelic (and Irish, and going further back to Old Irish) had two sets of consonants which linguists tell us are velarised and palatalised consonants such as [k] ~ [kʲ], [g] ~ [gʲ], [s] ~ [ʃ]. The [k], [g], [s] are velarized and the [kʲ], [gʲ] ,[ʃ] are palatalised, and so on, with other consonant sets.

But why? You might ask, what's wrong with just one set - either velarized or palatalized? The reason for this lies in the way our mouths work so when we speak we run sounds into each other. Mouth movements can cause a sound to affect the next sound, by carrying some of its features forward, or, a sound can affect a previous sound because the previous sound is anticipating the features of a sound that will be uttered next. So...

Imagine that very Old Irish only had one set of consonants - [b d g f k l m n r s t]. Now take the basic vowels that we most likely had in Old Irish: a u o e i and their long counterparts. There are many ways by which you could group these. But, the groupings that are important for us are the groupings of front vs. back. Say [e] & [i] - notice how they're both made at the front of your mouth? Now say [a] [u] and [o] - notice how these are made further back in your mouth? That's what we mean by front vs. back.

Now one of the few iron-clad rules of linguistics is that no language, no matter how mad, can make do with only consonants. We always have at least 1 vowel. Abkhaz for example has 50 or so consonants but only 2 real vowels. So we get sequences of vowels and consonants in very Old Irish, and these sounds influence and interfere with each other. Let's look at an example:

[kenːos]	Take "normal/basic sounds" such as [k] [e] [nː] [o] and [s] Now the fun part starts. Throw them together and the pesky little vowels start affecting the consonants.
[kʲeNːos]	Because the [k] is followed by a front (=palatal =slender) vowel, your tongue anticipates this and instead of making the [k] where you'd make it in English (at your velum), it moves forward a bit towards your palate. The [nː] has been dragged back and changed to [N because it's followed by a back (=velar =broad) vowel. The [s] in the -os ending hasn't changed because the only vowel around it is the [o] preceding it and that's a back (=velar =broad) vowel.
[kʲeNː]	Now we lose the ending just because endings often get lost and since the ending had already fixed the [Nː] as broad, it remained broad. Enter the medieval monks who decided they wanted to write Irish. Hard pressed with only 14 consonants from the Latin alphabet, and over 50 sounds in Old Irish which all needed writing down, they came up with something that was pure genius. They realised that Irish had a "grouping system" of consonants in which one group was generally surrounded with vowels of Group 1 and another group was generally surrounded by vowels of Group 2. So, more or less, they set down a rule saying that a consonant which is surrounded by Group 1 vowels (e i) will be a Group 1 consonant, in terms of pronunciation, and a consonant which is surrounded by Group 2 vowels (a u o) will be a Group 2 consonant, in terms of pronunciation. Oh, they also figured that you can show a long vowel by sticking a line over a vowel and that you can show a long consonant by writing it double. So where does that leave us? 2 x 11 consonants = 22 +5 doubled consonants = 27 +5 vowels = 32 +5 long vowels = 37 +8 lenited consonants by placing a dot above = 45. This gets us much closer to our target of 50 or so. And suddenly we can write Irish.
cenn [kʲeNː] ⇨ ceann [kʲeNː]	Hmm, still a bit messy because you can't really tell from the spelling whether the nn is broad or slender. So what do we do? We stick in a silent vowel meaning it does not get pronounced. Now the very velar nn starts affecting the vowel and drags it towards a more velar vowel - and at the same time the length shifts from the nn to the vowel - simply because it's much easier to say a long vowel as opposed to a long consonant.
ceann [kʲaːN]	This is how you still pronounce this word in Irish and in places like Kintyre and Argyll. In most other places though the long vowel has changed into a diphthong.
ceann [kʲauN]	Look and sound familiar?

So that's what this broad and slender business is really about. It's a way of telling you whether a sound has been dragged back in your mouth (=broad =velar) or forward (=slender =palatal). And the "silent" letters are there to make life easier for you.

Footnotes?

You betcha. First, Scottish Gaelic has lost some sounds. There used to be a slender [bʲ] [pʲ] [mʲ] [fʲ], but that distinction has been lost and replaced by a [j] glide before back vowels, and before front vowels, it's gone completely, e.g. bidh [biː]. What's the difference? The difference is that [bʲ] is one sound made with one smooth motion in your mouth. However, in modern Gaelic we get [bjɔː] beò in which three sounds are heard: [b], [j]. and an [ɔː].

Irish still has that distinction so you get pairs like bí [bʲiː] and buí [biː] where you can only tell the difference between to be and yellow by looking at the b.

Oh and by the way...

What else? Want to know why, in a lot of cases anyway, the genitive palatalises in Gaelic?

Going way back, there used to be simple endings which got stuck on the back of words to show cases, such as nominative and genitive. In the case of masculine nouns, the nominative ending used to be -os and the genitive ending used to be -i.

See it already? If the -os in [kenːos] is the reason why the -nn in modern ceann is broad, then the -i in [kenːi] must be the reason why we have cinn today. It goes like this:

• You start with [kenː] and from that, there are two different paths that lead to modern ceann (with the /au ~ a/ sound) and cinn (with the /i:/ sound).
• The first path has ken adding the os ending. Because [o] is a back vowel, meaning that it is made further back in the mouth, it forces the originally plain [n] into becoming dental and velarized.
• The other path seens [kenː] adding an [i] ending. Now [i] being a front vowel, meaning it is made toward the front of the mouth, it forces the original plain [n] into becoming a palatal [Nʲ].

So we get [kenːi] » [kʲeNʲːi] » [kʲiːNʲ] which shows that the -i has pulled the [e] upward whereas -os dragged the [e] downward.

Sin agaibh e!