Symbolism, Imagery, Allegory
Future people use funny language. They say "fasure" when they mean "certainly," they say "intersee" when they mean something like "understand" and "see with me."
To some extent, the word changes are just a way to make the future seem more future-y—like giving your future warrior a laser instead of a plain old gun. But some words are also meant to give you a sense of what the future is like.
Check out the word "per." "Per," short for "person," is used (not always, but often) in place of the pronouns "him" or "her"—as in
Person said that White Cloud was the bravest individual person had ever known because when Laughing Bear slandered per, White Cloud had given Laughing Bear a horse. (10.171)
"Per," then, means a person of either gender; it's a way of using a pronoun without having to specify whether that person is male or female. And it shows the reader that Mattapoisett is a place where gender matters less, and equality matters more. This one little word sums up the radical changes in gender norms that have happened in the future: men breastfeed, babies are born in tubes, and the workload is spread across the genders evenly. You don't need to know, or care, whether someone is a man or a woman to talk about per—because all people are (when it comes to working, at least) the same.