L.Sprague De Camp wrote a novel called The Wheel of IF in which England stayed with the Celtic form of Christianity (at the Council of Whitby, IIRC), the Norman Invasion didn't happen, and the conquest of North America came early so the native peoples held on to most of the continent. Most of the action takes place in the Bretwaldate of New Britain, roughly the east coast of the US, the Midwest is an independent Native American State, Mexico is still ruled by the Aztecs, Spain is under Moorish rule, South America is partly Islamized,etc. Of interest to this list is the dialect of the Bretwaldate which is English without the Norman French words and somewhat different sound changes. Knicks are police, Thock is thought, Shameful Outputting is indecent exposure,the choke of a steam car is the strangle, etc. The culture has a lot of Viking traits as well. De Camp had considerable linguistic knowledge and published professionally on American English dialects as well as popular science and history books, SF and fantasy.