Answer Verbs or Thuirt vs Thubhairt and what's in it

Most people have come across these doublets, but few have encountered any helpful explanations. Most explanations just present them as variants of the same 'thing'. Some say the longer forms are the 'old way' of spelling them, and there are a few sources which refer to them as stressed and unstressed forms. The latter is certainly true - but it actually goes beyond that. To begin with, here's a list of the most commonly seen variations:

an dubhairt thu?	[əN du.əRʃdʲ u]	an duirt thu?	[əN duRʃdʲ u]	did you say?
bhitheadh tu	[viːəɣ du]	bhiodh tu	[vjəɣ du]	you would be
bithidh tu	[bi.ɪ du]	bidh tu	[bi du]	you will be
thabhair dhomh	[ho.ɪrʲ ɣõ]	thoir dhomh	[hɔrʲ ɣõ]	give me

So many things in Gaelic orthography seem to be random, but really they aren't. This isn't either, and these spelling differences surface with some of the most commonly used verbs. They're reflecting a phenomenon of spoken Gaelic which shows distinction between what I've chosen to call "neutral forms" and "stressed forms".

"Neutral" means that the verb is used without putting particular stress on it, for example, because something else is stressed in the sentence or because you're making just a simple statement or question. "Stressed" means that for whatever reason, such as answering a question or stressing the verbal element of the sentence, you're putting emphasis on the answer.

This distinction is very common in languages; however, they differ in how exactly they do it. Gaelic does it two ways. It lengthens the vowel of the stressed verbs and splits the single syllable into two. Huh?

Well, let's look at an example:

Thuirt mi ris dol ann	[huRʃdʲ mi rʲiʃ ə ɣɔL aũN]	I told him to go there.
An dubhairt?	[əN du.əRʃdʲ]	Did you?
Thubhairt!	[hu.əRʃdʲ]	I did!

The first thuirt has quite a short vowel and just one syllable. But the other two become somewhat "drawn out" and two syllables are heard. It's similar to the difference in the English "Yes" and "Ye-es" (the kind of answer you get from some teenagers). Although it's the same vowel, it's longer, and there's a kind of break in between.

So what about other verbs, like tha and bha? In general, there's a tendency to lengthen the vowels slightly in stressed verbs and for the vowels to be short, or even disappear:

Mhol mi an latha dha	[vɔL mi N La.ə ɣa]	I greeted him.
An do mhol?	[əN də vɔL]	Did you?
Mhol!	[vɔˑL]	Yes!
Bha mi ann	[va mi ãũN]	I was there.
An robh?	[ə Rɔ]	Were you?
Bha!	[vaː]	Yes!

In Mhol! the vowel gets ever so slightly lengthened. This can be observed when measuremets are taken of vowel lengths. However, the slight lengthening of the vowel is by no means enough to make it sound like *mòl.

So it actually makes sense to have thubhairt AND thuirt when you're writing Gaelic. But, however you write it, the important thing is to remember to pronounce them properly when speaking.