Nations:
Tellewen: Tellewyn will be similar to medieval England in culture
Mallouhide: Mallouhide is very Tellewynian. They speak the language, and they have Tellewynian culture. However, its natives were very Irish inspired, and many lands retain their Irish names.
Delania: Scottish, not much more to say
Other Halfland Kingdoms: Cornish, Manx, Brittanic.