Broad A

Broad A is a name given to the pronunciation of the vowel sound of the letter A in words such as laugh, can't, and dance in most varieties of southern British English. Specifically, it refers to these words when they are not pronounced with the older pronunciation of /æ/ (SAMPA /{/ ) that is standard in most versions of North American English. Phonetically, the sound is [A:] in some older accents (such as Received Pronunciation) and further forward, [a:], in most younger accents.

Formerly, all dialects of the English language had the sound of /æ/ as in cat ( /kæt/ ) in all of these words. At some time, probably during the late eighteenth century, a sound change occurred in southern England that changed the sound of /æ/ to SAMPA /A:/ in words in which the former sound appeared before /f, s, th, v, z/, either alone or in the company of /m/ or /n/. RP pahth for path and vahz for vase are the result of this sound shift. It does not occur before other consonants; thus all varieties of British English, like American English, preserves the contrasting "flat a" in words like cat. The broad A was considered sub-standard or "Cockney" as recently as 1900 but is now a characteristic of the prestige Received Pronunciation and other accents now considered standard.

Variations

The change did not happen in all eligible words. It is hard to find a clear reason why some changed and others did not. Roughly, the more common a word the more likely that the change from flat /æ/ to broad /a:/ took place. It also looks as if monosyllables were more likely to change than polysyllables. Here are some examples to illustrate the variety:

Broad /a:f/ in half, calf, laugh, laughter, chaff, shaft, raft, after, and /a:v/ in halves, calves
Flat /æf/ still in baffle, raffle, Taffy, Aphrodite, kaftan and /æv/ in avid, navigate
Broad /a:T/ in path, bath, and /a:D/ in paths, baths, rather
Flat /æT/ in mathematics, maths, Cathy, and /æD/ in fathom
Broad /a:s/ in class, pass, mast, past, master, plaster, castle, mask, task
Flat /æs/ in ass (donkey), crass, mass (amount), classic, pastel, asp, Aston, Asquith
Broad /a:nt/ in aunt, plant, can't, advantage
Flat /ænt/ in ant, banter, cant (slang), scant, mantle
Broad /a:ns/ in dance, chance, advance, answer
Flat /æns/ in ransom, cancer, Anson

For speakers from the south of England, the As in all the above words are pretty consistently distinguished. The use of a broad A is one of the things that distinguish speakers in the south of England from more northerly speakers. However, broad As in the words half, calf, rather, aunt, can't and vase are more widespread in England.

There are some words in which both pronunciations are heard among southern speakers:

Greek elements as in telegraph, blastocyst, chloroplast
the prefix trans-
the word mass (church service)
the word lather

Use of broad A in mass, lather is distinctly conservative and probably rare now. However, the other two fluctuations are both common. There are further complications here. While graph, telegraph, photograph can have either, graphic, graphology always have flat A. The broad A is more likely in /tra:ns/ (transfer, transport) than in /trænz/ (translate, trans-Atlantic).

Southern Hemisphere accents

Evidence for the date of the shift comes from the Southern Hemisphere accents, those of Australia, New Zealand, and South Africa.

In Australian English, there is generally agreement with southern British in words like path, laugh, class. But before N+consonant, as in dance, plant, some Australians use a flat A (aunt and can't are exceptions and are invariably pronounced with /a:/). Phonetically the broad A is [a:]. In Australia there is variation in the word castle, both pronunciations being heard. For more information, see the table at Australian English - Regional phoenetic variation and Regional accents of English speakers - Australia.

South African and New Zealand accents have a similar distribution of sounds to Australian. New Zealand accents are more likely to use the broad version.

North America

The only areas of North America affected at all by the broad A are parts of New England and the Canadian Maritimes. In these areas, in the context where British speech has /a:/ or /A:/, both /æ/ and /A:/ tend to fall together into /a:/ or /ä/ (centralized /a/). This may preserve the conditions that led to the change in British English, but in fewer words such as can't; aunt; ask; bath; etc.