Spelling and pronunciation
In a few cases, essentially the same word has a different spelling which reflects a different pronunciation. Commonwealth as United Kingdom except where noted.
UK U.S. Remarks
aluminium aluminum Aluminium is the international standard in the sciences (IUPAC). The American spelling is nonetheless used by many American scientists. The original name proposed for the element was "alumium", with the name "aluminum" being suggested later. The name "aluminium" was finally adopted to conform with the -ium ending of many elements.[1] Canada as U.S.
arse ass In vulgar senses "buttocks" ("anus"/"wretch"); unrelated sense "donkey" is ass in both. Both forms are found in Canada and Australia.
barmy balmy In sense "slightly insane", "crazy", "foolish",[2] which has limited currency in American English. Both forms originated in 19th century England from other senses: barmy meant "frothing [as of beer]"; balmy means "warm and soft [as of weather]".
behove behoove Canada has both. British form is more etymologically conservative (Old English behōfian → Middle English behove(n)).
carburettor carburetor The British pronunciation stresses the third syllable; the American stresses the first. Canada as U.S.
charivari shivaree, charivari In the U.S., where both terms are mainly regional,[3] charivari is however pronounced usually as shivaree, which is also found in Canada and Cornwall,[4] and is a corruption of the French word.
coupé coupe for a 2-door car; the horse-drawn carriage is coupé in both; unrelated "cup"/"bowl" is always coupe. In the U.S., the E is accented when used as a foreign word.
eyrie aerie Rhyme with weary and hairy respectively. Both spellings and pronunciations occur in the U.S.
fillet fillet, filet Meat or fish. Pronounced as in French in the U.S. if spelled filet (more common). Canada as U.S.
furore furor Furore is a late 18th-century Italian loan that replaced the Latinate form in the UK in the following century,[5] and is usually pronounced with a voiced e. Canada as U.S. Australia has both.
haulier hauler Haulage contractor; haulier is the older spelling.[6] In Canada, hauler prevails.
maths math Abbreviations of mathematics. Canada as U.S. and an increasing use of math in some Australian states due to U.S. influences, although maths still prevails in Australia. New Zealand uses maths.
moustache mustache In the U.S., according to the Merriam-Webster Collegiate Dictionary and the American Heritage Dictionary, the British spelling is an also-ran, but the second-syllable stress pronunciation is a common variant.
mum(my) mom(my) Mother. Mom is sporadically regionally found in the UK (West Midlands English); some British dialects have mam,[7] and this is often used in Irish English. Canada has both. In the U.S. region of New England, especially in the case of the Boston accent, the British pronunciation of mum is often retained, while it is still spelt mom.
pernickety persnickety Persnickety is a late 19th-century North American alteration of the Scottish word pernickety.[8]
quin quint Abbreviations of quintuplet.
scallywag scalawag In the U.S. (where the word originated, as scalawag) scallywag is not unknown. By and large, Canada as U.S. and Australia as UK.[9]
s****** snicker According to major dictionaries, both forms can occur in both dialects, although s****** can cause offense in the U.S. due to the similarity to ******. In Canada s****** can have malicious connotations; in Australia s****** prevails, as in the UK.[10]
speciality specialty In British English the standard usage is speciality, but specialty occurs in the field of medicine,[11] and also as a legal term for a contract under seal. In Canada, specialty prevails; in Australia both are current.[12]
titbit tidbit Canada as U.S.
[edit] Latin-derived spellings
[edit] -our / -or
Most words ending in unstressed -our in the United Kingdom (e.g. colour, flavour, honour) end in -or in the U.S. (e.g. color, flavor, honor). Most words of this category derive from Latin non-agent nouns having nominative -or; the first such borrowings into English were from early Old French and the ending was -or or -ur.[13] After the Norman Conquest, the termination became -our in Anglo-French in an attempt to represent the Old French pronunciation of words ending in -or.[14] The -our ending was not only retained in English borrowings from Anglo-French, but also applied to earlier French borrowings.[15] After the Renaissance, some such borrowings from Latin were taken up with their original -or termination; many words once ending in -our (for example, chancellour and governour) now end in -or everywhere. Many words of the -our/-or group do not have a Latin counterpart; for example, armo(u)r, behavio(u)r, harbo(u)r, neighbo(u)r; also arbo(u)r in sense "shelter"; senses "tree" and "tool" are always arbor, a false cognate of the other word. Some 16th and early 17th century British scholars indeed insisted that -or be used for words of Latin origin and -our for French loans; but in many cases the etymology was not completely clear, and therefore some scholars advocated -or only and others -our only.[16]
As early as 1755 Dr Johnson settled on -our, while Webster's 1828 dictionary featured only -or and is generally given much of the credit for the adoption of this form in the U.S. By contrast, Johnson, unlike Webster, was not an advocate of spelling reform and for the most part simply recorded what he found. For example, documents [4] from the Old Bailey, the foremost court in London, support the view of the OED that by the 17th century "colour" was the settled spelling. Those English speakers who began to move across the Atlantic would have taken these habits with them and H L Mencken makes the point that, "honor appears in the Declaration of Independence, but it seems to have got there rather by accident than by design. In Jeffersons original draft it is spelled honour. " [5] Examples such as color, flavor, behavior, harbor, or neighbor scarcely appear in the Old Bailey's court records from the 17th and 18th century, whereas examples of their -our counterparts are generally numbered in hundreds. One notable exception is honor: honor and honour were equally frequent down to the 17th century,[17] and Honor still is, in the UK, the normal spelling for a person's name.
Derivatives and inflected forms. In derivatives and inflected forms of the -our/or words, in British usage the u is kept before English suffixes that are freely attachable to English words (neighbourhood, humourless, savoury) and suffixes of Greek or Latin origin that have been naturalised (favourite, honourable, behaviourism); before Latin suffixes that are not freely attachable to English words, the u can be dropped (honorific, honorist, vigorous, humorous, laborious, invigorate), can be either dropped or retained (colo(u)ration, colo(u)rise), or can be retained (colourist).[18] In American usage, derivatives and inflected forms are built by simply adding the suffix in all environments (favorite, savory, etc.) since the u is absent to begin with.
Exceptions. American usage most often retains the u in the word glamour, which comes from Scots, not Latin or French; saviour is a common variant of savior in the U.S.; the name of the herb savory is thus spelled everywhere (although the probably related adjective savo(u)ry does have a u in the UK). The British spelling is very common for "honour" (and "favour") on wedding invitations in the United States.[19]
Commonwealth usage. Commonwealth countries normally follow British usage. In Canada -or endings are not uncommon, particularly in the Prairie Provinces, though they are rarer in Eastern Canada.[20] In Australia, -or terminations enjoyed some use in the 19th century, and now are sporadically found in some regions,[21] usually in local and regional newspapers, though -our is almost universal.
Sorry for the double post but thought this could add more debate!