Ever noticed that your computer and phone speak a different dialect of English from yours? How they think 'colour', 'analyse' and 'centre' are spelling mistakes when you know for a fact that they are spelled correctly? For the most part, those of us who write the Queen's English have become so used to being erroneously corrected by our computers that we don't even notice it any more.
It's time to do something about it.
Very broadly, there are two main English 'dialects' when it comes to spelling. The main differences are in word endings...