I am curious about the history of linguistic change that brought American and British English apart, mostly pronunciation wise but also with regard to vocabulary. I assume that American colonial English was very similar to British English. Since then, they have grown far apart, either because modern British pronunciation has really changed since the 17th and 18th centuries or because American pronunciation evolved, perhaps due to an influx of immigrants who tended to speak differently than the original Colonials. Now I know that both Britain and the United States each have a subset of different pronunciation patterns, regional vocabularies and expressions. But for the purposes of the question, lets consider the differences between British and American English in general.