Americanise or Americanize?

[natalie_1982]

I've always thought that to change the 's' to a 'z' in words like prioritise, apologise, agonise, finalise, etc is writing it the American way.  I have since been told that the original old English way is to use 'z' instead of 's'.  Personally I prefer the 's' to the 'z', can anyone clarify which I should be using?  (I'm in England).

[lonzuk]

http://www.worldwidewords.org/qa/qa-ise1.htm

Info here about it.

[RevShirls]

This question was asked in Arts and Literature a few days ago. Here is the link:

http://www.theanswerbank.co.uk/Arts-and-Literature/Question93903.html

[Russ88]

I don't have a citation for you, but am fairly certain following is correct. 

American English is more similar to that spoken around 1700 when many English came to America and of course brought their language.  The differences in the two "Englishes" arose from changes happening in England, while in many regards American English stayed the same, hence American English is similar to the "original old English way."

I think the other posts speak to correctness, i.e. -ise has become correct in England and should be used.