Varied spellings of words, even within a single document by a single author were not uncommon as late as the 18th Century. And when it comes to usage, the UK, US, and Oz/Kiwis are nations divided by a common language.
I've probably mentioned that one of my kids is attending a university in China. It's not in a city that has a lot of Westerners, so she has had some interesting experiences.
She is part of a reading group that is almost all Chinese, but reading books in English. She grew up in Silicon Valley, but found herself having to explain some of the local dialect and cultural stuff in To Kill a Mockingbird (which was published around the time I entered elementary school). A bilingual fly on the wall in that room would probably have died laughing.
Sometimes a Chinese friend asks her to explain an English idiom/slang phrase and she has to consult friends from the UK and Oz to see if anyone recognizes and explain it. Not always with success.
My spouse works for a hospice, and it is difficult for my daughter to explain that job, because the concept of hospice care is not in Chinese culture.