Here’s the truth, and if you’re British or Australian, you may not like it: when it comes to the suffix ize, as opposed to ise, the American standard is correct.
I have no idea what cultural forces made America more sensitive to English spelling than Australia and even Britain, or how the British English spell-check software on your computer got it so wrong, when the British used to know better.
The global spread of word-processing splits the world into an informed mob (Americans, who understand when to use ize and when to use ise) and an uninformed mob (the pink parts on the map) who have no idea but who consider anything other than ise to be dangerously radical.
Many now believe ise to be correct, conservative, consistent. By contrast, ize is seen by these people as new-fangled and brash.
Craving the firm foundations of the establishment, Australians have standardised ise as the correct national form. Proselytising for ize is to no avail. Text editing changes ize to ise by default.
(The Conversation’s style guide, bound perhaps by the view that sees ize as a radical US invention, requires me to use the ise suffix throughout this article except in examples given to illustrate my point.)
Crossing out the ise
A simple method, which is now only understood in America, determines when to use ise and when to use ize. Both are correct but only for certain types of word; and it is incorrect to consider either to be universal.
For anyone brought up on Greek and Latin, there is scarcely a moment of doubt as to which suffix applies. But it isn’t necessary to know classical languages to understand the distinction.
The suffix ize should be used for verbs that connote transformation; when something is turned into something else or grows or becomes something. Usually, you can recognise the form whenever there is a simpler version of the word that pre-exists.
So we say theorise (or I would write “theorize”):
(a) because we turn something into a theoretical condition
(b) because a simpler word already exists: theory. According to the US convention, it would be theorize.
The same with other Greek words such as harmonize, systematize, stigmatize, categorize, canonize, apologize and so on. Indeed, this form takes its z unchanged from the zeta used in present tense conjugations in Greek.
Romans similarly respected this convention, which can still be seen in Italian and Spanish infinitives of the form izar(e).
So for English words derived from Latin, we can authorize, civilize, familiarize, fertilize, formalize, fossilize, humanize, immortalize, legalize, memorize, nationalize, naturalize, neutralize, patronize, pulverize, realize, satirize, scrutinize, secularize and so on.
In each of these cases, a simpler word lies behind it: author, civil, familiar and so on. Also, any abstract nouns based on these verbs should take a z, such as authorization, civilization, legalization, nationalization, pulverization, realization.
If you cannot see either (a) the process of transformation or becoming or (b) a simpler word inside the longer form, the correct suffix is ise. It is the reason we must always write advise, comprise, demise, despise, devise, disguise, excise, improvise, incise, merchandise, revise, surmise, surprise.
Such Latin words take their s from a kind of past participle of verbs for “take” or “see” or “cut”. We also have to use an s for some Greek words, such as analyse, for which the derivation isn’t a verb but is based on the motif of dissolution (lysis) that already has a sigma in it. Americans often get that one wrong.
It’s what you know, not where you are
For centuries, the use of ize and ise suffixes has had less to do with geography than knowledge or the kind and degree of education. In the past, if you were well educated you knew which to use in any circumstance.
Today, however, we think it’s posh and extra proper to standardise everything and homogenise spelling, in ignorant denial of the history of language and its correct use.
In a world that has big things to worry about, such as global warming, you might ask: does it really matter? And sure, on a scale of crimes against heritage, the demise of the z is a minor concern. If I hypothesize rather than hypothesise (yuck), you still know what I mean.
Also, going against classical conventions, the French have long standardised verbs to iser, and we can hardly call them dunderheads.
But it doesn’t mean that the issue doesn’t matter at all.
It’s a bit like a decision to paint a Federation church uniformly white, bricks and all. True, this vandalism doesn’t go so far as to demolish the building. Gratefully, the damage is somewhat reversible, but it’s still a silly, somewhat uneducated and ugly facelift.
Language is a great repository of history and its quirks all tell wonderful stories. But more than that, language isn’t meant to be uniform and globalised. We shouldn’t feel that a text with ize mixed with ise is somehow inferior, inconsistent or flawed.
The zeal to iron out a logical diversity and to impose a single suffix indicates insecurity. It’s a failure to understand the marvellous organic treasury of semantic traditions that language represents.