I used to do some gigs in the Middle East. Even within single documents you'd find the same words spelled in both the British English and American English spelling.
As a Canadian, only found the 's' instead of 'z' in words that end with -ize unfamiliar. The other flip-flopping didn't bother me because it was essentially what I always see here at home with Canadian/American spelling norms.
Usually there would be a standard dictating how things should look and feel, and that would indicate spelling norms. But when there isn't a standard, I'd just consider who I think would be the next people who have to look at my work, and go from there.
I always felt though, that the lack of standardizing (or standardising, as the case may be) the language of choice is the type of thing that leads to hard-to-find bugs. There should never be the option to have both a getColour() and getColor() defined.
As a Canadian, only found the 's' instead of 'z' in words that end with -ize unfamiliar. The other flip-flopping didn't bother me because it was essentially what I always see here at home with Canadian/American spelling norms.
Usually there would be a standard dictating how things should look and feel, and that would indicate spelling norms. But when there isn't a standard, I'd just consider who I think would be the next people who have to look at my work, and go from there.
I always felt though, that the lack of standardizing (or standardising, as the case may be) the language of choice is the type of thing that leads to hard-to-find bugs. There should never be the option to have both a getColour() and getColor() defined.