When one of the caroling children at Scrooge's door doesn't run off with the others after Scrooge orders them to leave, Scrooge rants "Don't you understand the King's English?!" This phrase might seem like an anachronism, since Britain had no king when A Christmas Carol was written: Queen Victoria was on the throne. But it's an anachronism that makes sense for an older man like Scrooge. When Dickens's book was published, Victoria had only been queen for six years, and she was the first queen regnant in more than a century. Scrooge would have been born during the reign of King George III (reigned 1760-1820), so of course "the King's English" would be the version of the phrase he's heard through most of his life and instinctively says.
