Simply Grand
What's that supposed to mean? We'll tell you. While the sentence structure is pretty straightforward, and the vocabulary is relatively easy to understand, there's something just a little bit formal, sophisticated even, about the way the characters speak that makes us feel as though we are dealing with a tale from another time.
Okay, that's still a little vague, so we'll give you some examples. Instead of telling Oll and Giddon they've got fifteen minutes to get Tealiff out of the dungeon, Katsa says, "A quarter hour, no more" (1.11). And when Raffin wants Katsa to stop in for a visit, he tells her, "Come if you've time" (6.38).
Of course, all the royal titles (My Lady, Prince Someone, Lord This-and-That) add to the formal feeling as well, along with phrases like "it was well enough agreed" (16.18), "she was glad of Po's company" (16.21), and "she wasn't looking forward to her first encounter with the inhabitants of the castle" (34.38). So yeah, even though it's all pretty simple, it feels a bit grand too, which kind of makes us want to put on our best Downton Abbey voices as we read.