I'm not sure if it's significant, but I always wondered about the implications of Spock's line from Spectre of the Gun
: "The names were known in the annals of the opening of the western sector of America. The United States of America, that is
Of the Enterprise crew, there was a Vulcan, a Russian, a Scotsman (Scotty never mention being from the "UK"), and two Americans (from Iowa and somewhere in the south-east).
Spock used a term that would be recognized by the two Americans in the party, and then clarified for the two from elsewhere on Earth.