The many functions of a

Certainly, from a learner's point of view, it would seem that every language has a small, annoying word which has so many possible functions. In Albanian (yes, I did Albanian for a while, I've always like Albania though I've not yet been there) this happens to be të, which can be any of the following:

• a short form of a second person pronoun in the dative or accusative
• a short form of a third person pronoun in the dative or accusative - meaning that the short form "for him" and "for you" are identical
• a particle which forms the conjunctive
• a particle which forms the future conditional
• a particle which forms the jussive (i.e. it helps form a kind of imperative)
• a particle needed for some infinitive constructions
• the definite article before a noun

Once you get into it, it's not too bad but can still be a head-scratcher at times, trying to figure out what a you're looking at.

The vocative particle

This a [ə] is placed in front of a noun or proper noun when directly addressing a thing or person. It lenites and forces the noun or proper noun into the vocative case, if the noun has a vocative case. English doesn't have a vocative case. The closest English equivalent is "oh!", but the Gaelic vocative particle doesn't sound as corny when you use it, it's just, well, normal.

Before a vowel or fh-, the a disappears.

Seumas [ʃeːməs] »	a Sheumais! [ə heːmɪʃ]
James »	(oh) James!
fir [firʲ] »	fheara! [ɛrə]
men »	(oh) men!
Mórag [moːrag] »	a Mhórag! [ə voːrag]
Morag »	(oh) Morag!

The leniting article

Technically, this is not just a but a' [ə], with an apostrophe, but I included it, nonetheless. This leniting article takes the form a' and it lenites the following word. It appears before feminine singular nouns in the nominative and before masculine singular AND feminine singular nouns in the prepositional case, before b c g m p.

a' bhròg	the show
air a' bhalach	on the boy

The participle-forming particle

Similarly, this a also takes an apostrophe, a' [ə], but I've included it because as the leniting article, in spoken Gaelic, it also comes out as [ə]. This isn't Borge's spoken punctuation you know :)

It is the reduced form of ag and appears before anything that is not a vowel and not r. It appears before b c d f g l m n p s t, for example:

tha mi a' bualadh	I am hitting
tha mi a' lagachadh	I am weakening

The masculine possessive pronoun

No apostrophe this time, just a [ə], and it lenites everything.

a bhalla	his wall
a mhàthair	his mother
a mhàthair [N » n]	his snake

The feminine possessive pronoun

This is the reduced form of a h-, which you get before feminine nouns beginning with vowels. The only other difference from the masculine possessive pronoun is that this one doesn't lenite the noun. It's also pronounced [ə]:

a balla	her wall
a màthair	her mother
a nathair [N » N]	her snake

The infinitive particle

Please see Habemus infinitivum necne for a full exposé on what's with the infinitive in Gaelic. Here, I'm just giving a couple of brief examples. Also pronounced [ə], it appears in certain types of sentences before a verbal noun and it prompts lenition:

Bu toigh leam cù a cheannach	I would like to buy a dog
Tha mi airson ubhal a ròstadh [R » r]	I intend to roast an apple

The counting particle

The reduced form of a h-[ə h] appears before numbers up to twenty, starting with a consonant. It's used when counting numbers but not objects.

a còig	five
a seachd	seven

The reduced form of the preposition do

The preposition do often reduces to just a [ə]. It lenites consonants, and before vowels and fh it gets reduplicated as do dh' and also a dh'. And yes, it overlaps, almost completely, with de. In many dialects, even the full forms do and de are pronounced [də].

thoir a Mhurchadh e	give it to Murdo!
theirig a Mhiùghalaigh	go to Mingulay!

It regularly appears across all dialects before placenames i.e. before placenames, the full form do is very rare:

thalla a dh'Inbhir Nis	away with you to Inverness!
thig a Bharraigh	come to Barra!

The reduced form of the preposition de

The preposition de often reduces to just a [ə]. It lenites consonants, and before vowels and fh it gets reduplicated as de dh' and also a dh'. And yes, it overlaps with do, almost completely. In many dialects, even the full forms do and de are pronounced [də].

sguir a sheinn	stop singing!
dèan truinnsear a chlach	make a plate from stone!

The relative particle

The relative particle a [ə] marks a relative clause. That's it really...

cuin a sheinneas tusa?	when will you sing?
an tè a thuit	the woman who fell

The first part of various adverbs

Which is sadly relevant because of some GOC nonense. For some arcane reason, they took offence to the hyphen in an-seo, an-sin, and an-siud and re-spelled them as an seo, an sin and an siud. As if Gaelic didn't have enough words that are written an... Anyway, this means that people who have a tendency to write everything exactly as they say it, and who follow GOC a bit too religiously, sometimes reduce the an to a [ə]:

an-seo [əˈʃɔ]	a-seo [əˈʃɔ]	an seo [əˈʃɔ]	a seo [əˈʃɔ]
an-sin [əˈʃin]	a-sin [əˈʃin]	an sin [əˈʃin]	a sin [əˈʃin]
an-siud [əˈʃid]	a-siud [əˈʃid]	an siud [əˈʃid]	a siud [əˈʃid]

Yes, the n is almost always deleted in spoken Gaelic. If you pronounced it very carefully, it would be [əNʲˈʃɔ].

The letter a

To confuse matters, when a represents just the letter a, this is mostly read the English way i.e. "ay" even though Gaelic has very old indigenous names for the letters. But there are a few people who still know the old names of the letters.

a, b, c	[ɛj] [biː] [siː]
a, b, c	ailm, beith, coll

A dialectal form of e

In writing, in some dialects, people use a where you'd expect e, in order to represent the regional pronunciation of it, [a].

chonaic sinn a	[xɔNɪgʲ ʃiNʲː a]
chualaig a caile	[xuaLɪgʲ a kalə]

The interrogative particle

The reduced form of an [ən], appears only before bheil:

a bheil thu tinn?

are you ill?

The exclamation

This comes out as a clear [a]. Nothing much else to say about it really.

A, sin agad e

Ah, there you go

The preposition á

Of course, this has an acute - well, a grave these days - but added just for the sake of completeness. In this instance only, the acute/grave on á does not make it a long vowel. The acute is just there to distinguish it from other particles written a which are pronounced [ə], whereas á has a clear, short [a].

Thàinig mi á Peairt

I came from Perth