American and British English spelling differences

Spelling differences between U.S. usage on one side and British and Commonwealth usage on the other are generally more conspicuous than spelling differences within the Commonwealth. For this reason, the term Commonwealth English is used throughout this page to collectively refer to the spelling used in the British Isles and the English-speaking countries of the Commonwealth of Nations, as opposed to American spelling. Differences within Commonwealth usage are duly noted.

Many of the differences were introduced into the United States by Noah Webster's dictionary; he was a strong proponent of spelling reform for a variety of reasons, both nationalistic and philosophical. There were many advocates of spelling reform in England as well, but the influences of those who preferred the Norman (or French) spellings of certain words proved decisive. Some of the changes in American spelling were largely phonemic, while others involved the restoration of "etymologically correct" Latin (or Greek) spellings, often to words which English had borrowed from French (or indirectly, Greek) – color, Gk. διαλογος → Fr. couleur, dialogue → British English colour, dialogue. At the time, spelling in English was not regular, and Webster was eager to distinguish American usage from British usage – and in some cases to create distinctions. Although many of Webster's spellings became standardized in the U.S., only a few spread to other English-speaking countries, which were more influenced by Samuel Johnson's dictionary. (Webster's more radical suggestions for spelling reform made in his younger days, such as the dropping of silent "e" at the end of words, were not adopted anywhere.) However, in some cases the American versions have become common Commonwealth usage, especially with specific usages such as 'disk' in the sense of magnetic digital media, versus 'disc' for a flat circular object.

Spelling and pronunciation
In a few miscellaneous cases, essentially the same word has a different spelling which reflects a different pronunciation. Commonwealth as Britain except where noted.

-our / -or
Most words ending in unstressed -our in Britain (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. After the Norman Conquest, the termination became -our in Anglo-French and -our was not only retained in English borrowings from Anglo-French, but also applied to earlier French borrowings. After the Renaissance, 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 "bower"; 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. However, as early as 1755 Dr Johnson settled on -our, while Webster's 1828 dictionary featured only -or.

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, colourise/colourize, 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 (coloration, colouration), or can be retained (colourist). In American usage, derivatives and inflected forms are built by simply adding the suffix in all environments (favorite, savory, etc.)

Exceptions. The word glamour comes from Scots, not Latin or French, and is usually spelled glamour (rarely glamor) in the U.S. and glamour always elsewhere; 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 Britain.)

Commonwealth usage. Commonwealth countries normally follow British usage. However, in Canada -or endings are not uncommon, particularly in the Prairie Provinces. In Australia, -or terminations enjoyed some use in the 19th century, and now are sporadically found in some regions.

-re / -er
In Commonwealth English, some words of French or Greek origin end with a consonant followed by -re, with the -re unstressed and pronounced. Most of these words have the ending -er in the U.S. This is especially true of endings -bre and -tre: fibre/fiber, sabre/saber, centre/center (though some places in the United States have "Centre" in their names), spectre/specter (though spectre is acceptable in the U.S.). Theatre has started to take on a different meaning from theater in the U.S. The latter is a more general term, the former tends to be applied to live theatrical performances (i.e., not films). Macabre is an exception, perhaps because in the U.S., the word is regarded as French, and is even pronounced as a French word, if the final syllable is pronounced at all. The ending -cre is retained in America: acre, massacre, and so on; this prevents the c losing its hard k sound. There are not many other -re endings, even in Commonwealth English: louvre, manoeuvre, meagre, ochre, ogre, sepulchre, and euchre. In the U.S., ogre and euchre are standard, manoeuvre and sepulchre are usually maneuver and sepulcher, and the other -re forms listed are variants of the equivalent -er form.

Of course the above relates to root words; -er rather than -re is universal as a suffix for agentive (reader, winner) and comparative (louder, nicer) forms. One consequence is the Commonwealth distinction of meter for a measuring instrument from metre for the unit of measurement. However, while poetic metre is often -re, pentameter, hexameter, etc. are always -er.

The e preceding the r is retained in U.S. derived forms of nouns and verbs, for example, fibers, reconnoitered, centering, which are, naturally, fibres, reconnoitred and centring respectively in Commonwealth English. It is dropped for other inflections, for example, central, fibrous, spectral. However such dropping cannot be regarded as proof of an -re Commonwealth spelling: for example, entry derives from enter, which is never spelled entre.

-ce / -se
Nouns ending in -ce with -se verb forms: American English retains the noun/verb distinction in advice / advise and device / devise (pronouncing them differently), but has lost the same distinction with licence / license and practice / practise that Commonwealth spelling retains. American English uses practice and license for both meanings. Also, Commonwealth defence, offence, pretence; American defense, offense, pretense: but compounds such as defensive, offensive,  pretension, pretentious are always thus spelled.

-xion / -ction
The spellings connexion, inflexion, deflexion, reflexion are now somewhat rare in everyday usage, perhaps understandably as their stems are connect, inflect, deflect, and reflect and there are many such words in English that result in a -tion ending. The more common connection, inflection, deflection, reflection have almost become the standard internationally. However, the Oxford English Dictionary lists the older spellings as the etymological form, since these four words actually derive from the Latin root -xio.

Connexion is still used in legal texts. British Methodism retains the eighteenth century spelling connexion to describe its national organisation, for historical reasons, and this spelling has also found favour amongst recent government initiatives such as connexions (the national careers and training scheme for school early leavers). Until around 1984 and 1985, The Times of London also used connexion as part of its house style.

In both forms, complexion (which comes from the stem complex) is standard and complection is not. However, the adjective complected (as in "dark complected"), although sometimes objected to, is more common than complexioned in the U.S. but rare in Britain. Likewise, crucifiction is usually regarded as an error; crucifixion (from crucifix) is the correct spelling. (Etymologically, the spelling crucifiction would in any case mean not &ldquo;fixing to a cross&rdquo; (Lat. figere) but &ldquo;moulding into a cross&rdquo; (Lat. fingere)).

-ize / -ise
American spelling accepts only organize, recognize, and realize. British usage accepts both the older -ize form and the frenchified -ise form (organise, recognise, realise). However, the -ize spelling is rarely used in the UK in the mass media and newspapers, which is why it is often incorrectly regarded as an Americanism, even though it is preferred by some authoritative British sources, including Fowler's Modern English Usage and the Oxford English Dictionary, which until recently often did not list the -ise form, even as an alternative. The -ise form is used by the British government and taught in the British school system, and is more prevalent in common usage within the UK today. Pam Peters (2004, -ize/-ise), drawing on British National Corpus data, asserts that the ratio of popularity in Britain between -ise and -ize currently stands at 3:2. In Australia and New Zealand -ise spellings are strongly preferred; the Australian Macquarie Dictionary, among other sources, gives the -ise spelling first. Conversely, Canadian usage is essentially like American, although -ise is occasionally found in Canada. The same pattern applies to derivatives and inflections such as colonisation/colonization. Worldwide, using -ize in combination with British spelling is common in academic publishing (e.g. used in the science journal Nature, the WHO's ICD and ISO standards).

Endings in -yze are now found only in the U.S. and Canada. Thus, Commonwealth (including sometimes Canada) analyse, catalyse, hydrolyse, paralyse; North American analyze, catalyze, hydrolyze, paralyze. It is worth noting, however, that analyse was commonly spelled analyze from the first—a spelling also accepted by Samuel Johnson; the word, which came probably from French analyser, on Greek analogy would have been analysize, from French analysiser, of which analyser was practically a shortened form.

Note that not all spellings are interchangeable; some verbs take the -z- form exclusively, for instance capsize, seize (except in the legal phrase to be seised of/to stand seised to), size and prize (only in the "appraise" sense), whereas others take only -s-: advertise, advise, apprise, arise, chastise, circumcise, comprise, compromise, demise, despise, devise, disguise, and televise. Finally, the verb prise (meaning to force or lever) is spelled prize in the U.S. and prise anywhere else, including Canada.

-ogue / -og
Commonwealth analogue, catalogue, dialogue; American analog, catalog, dialog; and inflected forms: American cataloging, Commonwealth cataloguing. This applies with any consistency only to the various words ending in -log(ue) deriving from Greek &lambda;&omicron;&gamma;&omicron;&sigmaf;, although the -ue can be dropped in any word where there is a short o preceding the g: demagog(ue), pedagog(ue), monolog(ue), homolog(ue), etc. Note that, as with computer program, the word dialog in the context of computers (e.g. dialog box) usually uses the American spelling for all instances.

All the -gue forms are also relatively common in the United States, especially dialogue, which is the preferred variant in Merriam-Webster's dictionaries. Other words ending in -gue in Commonwealth usage generally retain -gue in America; for example, vogue, rogue, plague, intrigue, fugue, colleague, tongue, harangue.

Simplification of ae (æ) and oe (&#339;)
Many words are written with ae or oe in British English, but a single e in American English. The sound in question is or  (or unstressed ). Examples (with non-American letter in bold): anaemia, anaesthesia, caesium, diarrhoea, gynaecology, haemophilia, leukaemia, oesophagus, oestrogen, orthopaedic, paediatric. Words where British usage varies include encyclopaedia, foetus, homoeopathy, mediaeval. Words where American usage varies include aesthetic and oenology. Archaeology retains the a in both versions (although archeology is also accepted in American English, it is uncommon), although the ligature is usually dropped. This difference is also half of the distinction between British manoeuvre and American maneuver.

The Ancient Greek diphthongs &lt;&alpha;&iota;&gt; and &lt;&omicron;&iota;&gt; were transliterated into Latin as Æ| and . The ligatures æ and &#339; were introduced when the sounds became monophthongs, and later applied to words not of Greek origin, in both Latin (for example, f&#339;tus) and French (for example, &#339;uvre). In English, which has imported words from all three languages, it is now usual to replace Æ/æ with Ae/ae and &#338;/&#339; with Oe/oe. In many cases, the digraph has been reduced to a single e in all varieties of English: for example, oeconomics, praemium, and tragoedy. In others, especially names, it is retained in all varieties: for example, phoenix, Caesar, Oedipus. There is no reduction of Latin -ae plurals (e.g. larvae); nor where the digraph / does not result from the Greek-style ligature: for example, maelstrom, toe. British aeroplane is an instance (compare other aero- words such as aerosol). American airplane is not a respelling but a recoining, modelled on airship and aircraft. Airplane dates from 1907, at which time aero- was trisyllabic, often written a&euml;ro-.

Compounds and hyphens
Commonwealth English often favours hyphenated compounds, such as counter-attack, whereas American English discourages the use of hyphens in compounds where there is no compelling reason, so counterattack is much more common. Many dictionaries do not point out such differences.

Common suffixes
Commonwealth English generally doubles final -l when adding suffixes that begin with a vowel if -l is preceded by a single vowel, whereas American English doubles it only on stressed syllables. (Thus American English treats -l the same as other final consonants, whereas Commonwealth English treats it irregularly.) Commonwealth counsellor, equalling, modelling, quarrelled, signalling, travelled; American usually counselor (but chancellor), equaling, modeling, quarreled, signaling, traveled.
 * But compelled, excelling, propelled, rebelling in both (notice the stress difference); revealing, fooling (double vowel before the l); hurling (consonant before the l).
 * But Commonwealth fuelling, woollen; American fueling, woolen.
 * Commonwealth writers also use a single l before suffixes beginning with a consonant where Americans use a double: Commonwealth enrolment, fulfilment (but fulfilled), instalment, skilful; American enrollment, fulfillment, installment, skillful. The infinitives of these verbs are also different: in the Commonwealth, they are to enrol, fulfil and instal (although install is far more common), whereas in the USA, they are to enroll, fulfill and install.
 * Commonwealth English often keeps silent e when adding suffixes where American English doesn't. British usually ageing, routeing; American aging, routing. Both systems retain the silent e when necessary to preserve a soft c or g: traceable, judgement (although judgment is also standard in both Commonwealth and American English), and in the word dyeing to distinguish it from dying.

Miscellaneous spelling differences
Proper names formed as acronyms are often rendered in title case by Commonwealth writers, but usually as upper case by Americans: for example, Nasa / NASA or Unicef / UNICEF. This never applies to initialisms, such as USA or HTML.

There is a tendency for new technical meanings of old words to be coined in America and then re-exported to the Commonwealth with the American spelling retained, thus creating a written distinction between the old and new meanings which does not exist in American English. See disk, program and possibly artifact. But compare also meter, for which an older English written distinction between etymologically related forms with different meanings once existed, but was obviated in the regularization of American spellings.

Throughout the following table, Canadian and Australian spelling is the same as British except where noted. Where Australian spelling follows U.S. usage, New Zealand often prefers the British variant.