clever wording here; for Jade to know English would be for her to “understand terror no human ever has”, because for a troll, that kind of terror is just nature. that’s why Karkat has to be the one to wise her up to it.
understanding that Karkat’s fear of the fourth wall and his fear of his own otherself are two intertwined snakes, though, this page also seems to be playing a little dramatic prank on us. “what’s the name of the guy who wears this coat? unrelated but let’s listen to Karkat right now.” Karkat’s own voyeuristic tendencies flare up as he begs Jade: turn off that damn window, or any old pervert will be able to see into your house!
possibly a game of Twin Peaks is being played here, too… Jade can’t ever know the name of the guy in the coat because that means knowing it’s really her dear old Grandpa. but of course this brings us back to my first point: to Karkat’s race, knowing that dear old Grandpa was responsible all along isn’t a revelation, it’s just life.