Most American usage and spelling of English harks back to the late 15th & early 16th Centuries. They just didn't move on!
My bug bear is the expression "in back" or "out back" which I think means in the back garden or yard. Also the dropping of the word "the" is so annoying even when the English narrators are explaining deployment of various army divisions on a history program they refer to 5th army division rather than "the" 5th army division.