Compensatory lengthening and The secret of time

No, I'm not about to go mystic on you, no worries. But time does come into it. Now - just humour me for a moment, and enjoy:

V > V:; VV /_ C: [+son]#

V > V:; VV /_ C: [+son][αplace]C[αplace]

V > V / _ C:[+son]V

V > V / _ C:[+son][αplace]C[βplace] and α ≠ β

You know, when I started doing linguistics, quite some time ago, I thought I'd finally escaped maths. Hah! Anyway, that was just for enjoyment, I will make things clearer.

I'm sure you have all come across words like ann, ball, ceann and cam and wondered where the strange diphthongs come from? So why do we say [auN] and [kaum] and [bauL] rather than *[aN], *[kam] or *[baL]? OK, we can take the view that they're simply pronounced like that and we just have to learn those pronunciations by listening. Fair enough, listening is important. But some of us are a bit inquisitive, and we don't all have the privilege of living with a native speaker. As it turns out, there are a few very good pointers and they're less arcane than the above rules.

So here's what happened: Going back to Old Irish (again), we find a handful of interesting consonants. Long sonorants - that is, long l n r and m. They're called sonorants because when you say them you can create extended sound with them, almost as if they were vowels. The resonance that they can produce is something that doesn't work with p t k, for example. Because they were long, our kind scribes wrote them as double consonants, quite logical really. So we got:

Old Irish	Gaelic	Irish
lomm [Lomː]	lom	lom
tomm [tomː]	tom	tom
mall [maLː]	mall	mall
mell [mʲeLː]	meall	meall
cenn [kʲeNː]	ceann	ceann
donn [doNː]	donn	donn
corr [koRː]	corr	corr
cerr [kʲeRː]	cearr	cearr

So what? Well, it turns out long consonants are prissy, unstable sounds which don't hang around for long. What often happens is that the long consonants "transfer" their long quality to the preceding vowel. In many cases, in turn, the preceding vowel gets diphthongised which means it gets broken from one vowel sound into two vowel sounds. That happens in many languages, just think of the changes from Old English to Modern English: hlūd [luːd] became loud [laʊd], nama [naːmə] became name [neɪm]). The pronunciation daisy chain goes like this from Old Irish to Gaelic:

Old Irish ⇨	Middle Irish ⇨	Common Gaelic ⇨	Scottish Gaelic (most)
lomm [Lomː]	lom [Loːm]	lom [Loːm]	lom [Lɔum]

If the sonorant is followed by another vowel, this doesn't happen. This includes words with helping vowels, so words like Donnchadh escape both lengthening and diphthongisation. In linguistics, the order in which rules are put into action is called "rule ordering". Rule ordering means that when there are two rules which could both apply, the language usually has a preference for which to apply first and which to apply second. Usually, applying one means the other can't apply any more.

A good pair of words to remember here is caill [kaiLʲ] and cailleach [kaLʲax]; similarly ann [auN] and Anna [aNə].

This happens in virtually all surviving dialects of Gaelic. Some conservative (regarding lengthening) dialects of East Perthshire, Kintyre and Arran had kept the long consonants, never lengthened the vowel, and never dipthongized the vowel. But, today, those dialects are mostly moribund. So to be brief, all that needs to be said about these dialects is that in almost all cases they either lengthen the vowel, or simply have a short vowel, but hardly ever dipthongise the vowel. So, in Arran Gaelic for example ann, ceann, donn, cum and ionnsaich would be pronounced as: [aN] [kʲaN] [doN] [kum] and [iNsiç], and around Cowal that would be [aNː], [kʲaNː], [doNː], [kumː] and [iNːsɪç].

The most lively dialects today are fairly homogeneous, except perhaps for Lewis Gaelic (don't sigh) which is the most progressive among the dialects, but we'll deal with that later.

before ll	before nn	before m	before rr
a
call [kauL]	gann [gauN]	cam [kaum]	barr [baːR]
(e)ai
caill [kaiLʲ]	cainnt [kãĩNʲdʲ]	maim [maim]	feairrd [fjaːRdʲ]
ea
seall [ʃauL]	ceann [kʲauN]	dream [draum]	cearr [kʲaːR]
ei
beinn [beiNʲ]	greim [grʲeim]
i
cill [kʲiːLʲ]	binn [biːNʲ]	im [iːm]
io
	fionn [fjuːN]		sgiorr [sgʲu:R]
iu
		rium [rʲuːm]	tiurr [tʲuːR]
o
toll [tɔuL]	fonn [fɔuN]	tom [tɔum]	torr [tɔːR]
oi
goill [gɤiLʲ]	roinn [RɤiNʲ]	stoim [sdɤim]
u
a-null [əˈNuːL]	grunn [gruːN]	cum [kuːm]	sgurr [sguːR]
ui
tuill [tɯiLʲ]	cluinn [kLɯiNʲ]	druim [drɯim]

Lewis just extends the breaking to [iː] and [uː] so you get cum [kɔum] and ìm [ɤim] etc.

So how does this all relate to the Secret of Time? What's Gaelic for time? Àm, isn't it? Or is it am? Consider Cùm or cum and Ceàrr or cearr? Strictly speaking, as long as you're aware of the rules of lengthening/diphthongisation (easy if you're a native speaker) there's no need really to indicate length over the vowels. Whatever GOC says, it's up to you, in a way, because the grave is surplus to requirements. But, anyway, those are the secrets behind the confusion arising over words like àm vs am.

However, watch out for the derivatives of these words. Remember that a following vowel prevents a long vowel or a diphthong from appearing. So, because many words add a vowel to indicate the genitive, or add an ending to form a verbal noun, you must not pronounce or write a long vowel/diphthong in the derived word. Here are a few illustrative examples:

àm	⇨	clàr-ama, amannan...
barr	⇨	Dùn Bharra, barrachd...
gearr	⇨	a' gearradh, a ghearras, gearraidh...
ceann	⇨	a' ceannach, a cheannaicheas...
cum	⇨	a' cumail, a chumas, cumaidh...
tinn	⇨	nas tinne, tinneas...

My personal recommendation is that you do not put this superfluous accent onto vowels in these positions. If you do, it will just mess things up, especially for learners. But I've even heard the odd native speaker get this pearshaped when reading a text out loud. The only exceptions are:

• words which always have a long vowel/diphthong (féill, dìlleachdan, ciùrradh, ciùrrail, gàrradh...)
• two letter words like ìm and àm, technically not necessary either, but that's a usage that's fairly old, presumably because of the potential overlap between the definite article and àm.

So in a nutshell:

A vowel before ll nn rr and m will get lengthened or diphthongised except if is followed by a vowel

So. Happy diphthongising to you all!