Use of 'z' versus 's' [duplicate]

Question

I've been brought up believing that most of the words that have suffix with '-ize' or '-ized' is the American English form and the British English forms use (most of the time) '-ise' or '-ised' as the equivalent.

Two questions:

1) What is the rule, if any, around exception cases, i.e. choice of one or the other in a single form (dialect?) of English?

2) I have read recently, on Wikipedia admittedly, that the etymology of these terms is such that the correct form anyway, for all English from Greek roots, is '-ized' using the 'z'. This contradicts what I see, and what I've been brought up to know. But is that correct - it was from this site:

http://www.metadyne.co.uk/ize.html

and the Wikipedia page.

I am not saying it is wrong, but I wanted to verify if this is the case...as I say, it runs contrary to what I know, but came across it by chance and it is a very difficult habit to get out of. I don't want to do it (as a British person, using '-ise' all the time) to the American English version, when actually it would be wrong.

On a more pragmatic matter, I wonder if doing this is a bad idea anyway in the UK, since most people are told the 's' version is correct.

Finally, etymologically, what is the reason for this shift across, whatever the reason is? And is it something that is 'wrong' or more 'the development of language over time'.

I don't understand why America would revert to 'z' after the development of English in Britain towards 's', given that Greek is the origin. I understood British people discovered America and brought British English over there. Unless, and probably quite likely, I haven't got a clue re the history between the two nations (and this is not meant to offend, I just have a confused understanding - sorry if it does).

Answer 1

Indeed, Greek is one linguistic source in questions of "-ize" vs. "-ise", with the latter looking to the added lens of French. Greek's "zeta" / "-ize" is preferred (but not exclusively so) in the U.S. while French intervocalic "s" / "-ise" is preferred in Britain. There are exceptions: the French "s" prevails in both countries in words such as "surprise" (from the past participle of French "surprendre") where there is no equivalent cognate from Greek. 19th century American prescriptions for spelling favored classical languages (Latin as well as Greek) as sources, while British English never "forgot" (linguistically) the influence of the Norman Conquest, which brought French to Anglo-Saxon shores - hence the continued preference in Britain for the presence of "u" where it occurs in French, e.g. UK: vapour (Fr. vapeur) as opposed to US: vapor (Latin vapor).