Why do Brits and Americans spell differently?
Why did Americans drop the “u” from British words like “humour” and “behaviour”? What about “theater” vs. “theatre”?
Here are some answers. I hope it helps you!
Want even more info? Check out these websites 🙂
https://en.oxforddictionaries.com/spelling/british-and-spelling
http://www.bbcamerica.com/anglophenia/2014/05/america-drop-u-british-spellings/
https://en.wikipedia.org/wiki/American_and_British_English_spelling_differences
– Belén
