Most people think of an accent as something that other people have. In some cases, they speak disparagingly about one accent compared with another. The truth is that everyone has an accent, because an accent is simply a way of pronouncing words. The reason that you can tell the difference between people from Boston and the Appalachians, or between London and Manchester is because each group of people has a different way of pronouncing the same words. In other words, accent is all about sound.
When it comes to changes in vocabulary in different regions, then you’re talking about dialect. Dialect refers to differences in accent, grammar and vocabulary among different versions of a language. For example, depending on where you live in England, one type of baked goods could be called buns, cobs or rolls. It is likely that when you speak in the dialect of a particular region, you will also speak in the accent of a particular region. However, incomers may speak the dialect of a region with a different accent. This may also apply to people who have emigrated from one country to another. They may speak a different form of a language from those born in that country.
So, what does all this have to do with writing? It’s simple. Most written English is based on a dialect of English. The variety of English known as standard English uses a certain type of grammar and vocabulary which is taught to students of English all over the world. They may speak with a different accent, but the dialect is basically the same.