Face it, we English speakers (which presumably includes you, since you’re reading this) don’t always read and write the same language, even if we all call it English. Sure, someone trying to communicate in a language that isn’t their native language may have a harder time being understood. But we understand that and make allowances for it. I talk more slowly (usually) when I’m not speaking English, and my listeners don’t expect me to speak perfectly.
From my perspective as an American Southerner, it seems that US Americans and Canadians are the only English speakers who don’t sound at all like someone from England. To me, Australians and Kiwis (New Zealanders) speak with a British accent. The English of an educated South Asian or West African is also derived more directly from England than my English.
A few decades ago, even we North Americans weren’t so proud and independent in our language. Noah Webster may have produced the first distinctive US American dictionary way back in 1828, but whenever we wanted to sound more cultured, our speech became more British. They call it a mid-Atlantic accent, somewhere between British and American.
Sometimes native English speakers from different countries have more trouble communicating with each other than non-native speakers. That’s because we are all convinced that the English we speak is the “real” English. If we believe that real English must always be spoken rapidly, we can’t make ourselves slow down even when our listener doesn’t understand us. The English spoken by people of our own country becomes our model for proper English. Unfortunately, the English spoken by people of our listener’s country becomes their model for proper English, and they may resent it when we don’t understand that.
What does this have to do with writing?
Whether writing or speaking, if you want your message to be understood, something’s got to give. And that something is always you. Your readership determines what kind of English you use. An advertising copywriter never says, “Learn to talk and think like me so you can buy my product.” Rather, every copywriter learns to write in the language of his or her readers. That goes beyond national differences.
When I write for British or Canadian readers, of course I will write “honour” and not “honor.” But every region, every generation, every sub-group speaks and thinks differently, even almost imperceptibly. Even the word “honor” communicates better with some people than others. A different group of people might prefer a different word for the same concept. And I must not cling to language that I appreciate and understand if my reader doesn’t understand and appreciate it too.