-ise - -ize

From Awe

The common belief (and practice) is that the ending of verbs which terminate with the sound '-EYEZ' (IPA: /aɪz/) are spelled with a z in American English, but an s in British English. This is not so: the matter is more complex than that. (This is partly because Noah Webster rejected '-ise' as being etymologically improper, in his declaration of American independence of spelling.) The advice of OED, Hart's Rules and Burchfield's Fowler (all authorities on British English) is simple: that the normal form should be -ize. There are of course exceptions. The most glaring is the different house rules of different publishers. The three authorities cited here are all published by Oxford University Press, so they all agree: other publishers have different rules. Cambridge University Press and the Guardian both standardize on -ise - as does Microsoft Word's spell-checker when set for 'English UK'. Burchfield's Fowler says "The primary rule is that all words of the type authorize/authorise, civilize/civilise, legalize/legalise may legitimately be spelt with either -ize or -ise throughout the English-speaking world, except in America, where -ize is compulsory" (s.v -ize, -ise in verbs, 2). The same, of course, is true of such derivatives as the nouns formed with '-ation': the etymologically preferable termination is -ization, but several publishers prefer '-isation'. As always, do what your reader wants. If you are a student, follow your marker's preference.

This is because, to summarize OED's etymological explanation (s.v. -ize), the origin of the suffix is Greek, in which language, as in classical Latin, the spelling was with '-z-', or its equivalent ζ (zeta; upper case form Ζ). From the spelling of the infinitive which became standard in French, i.e. -ise(r), many Latin words which were adopted (many of Greek origin) by modern and medieval French were written with the '-s-'. So the practice grew - in the days when French was a prestigious language - of writing the termination as -ise for all these words. Some well-educated people prefer to use it for words that were first formed in French, using -ize for those of older formation. We cannot all aspire to make such nice distinctions. OED is unequivocal: "the suffix itself, whatever the element to which it is added, is in its origin the Gr. ιζειν, L. -izare; and, as the pronunciation is also with z, there is no reason why in English the special French spelling should be followed, in opposition to that which is at once etymological and phonetic." In OED itself, "the termination is uniformly written -ize." AWE would regard this example as being good enough to follow. But we also remember Emerson's advice on consistency, and do not claim to have used -ize without exception - not least because many spell-checkers insist on -ise in what they regard as British English.

Hart gives a list of 30 common verbs which are properly spelled with -ise. These, along with some others, can be found in category:verbs spelled with -ise. Hart's list is not quite identical with that in Burchfield's Fowler s.v. -ise, 1.

According to wikipedia, citing Peters, 2004, "The ratio between -ise and -ize stands at 3:2 in the British National Corpus....." It also makes a point that may help international scholars, particularly in the sciences: "Worldwide, -ize endings prevail in scientific writing and are commonly used by many international organizations." [1].

Note that capsize is never spelled with -ise'.

See also -lyse - -lyze