Soon after Huck and Jim begin their journey down the Mississippi River on their raft, Jim describes his experience using hyperbolic language that Huck appropriates for himself as well:
Jim said it made him all over trembly and feverish to be so close to freedom. Well, I can tell you it made me all over trembly and feverish, too, to hear him, because I begun to get it through my head that he was most free—and who was to blame for it? Why, me.
In declaring that he felt “trembly and feverish to be so close to freedom,” Jim uses a hyperbole to explain the extreme excitement and joy that comes from leaving a life of slavery behind him. By using hyperbolic language here, Twain establishes how high the stakes were for runaway enslaved people. Jim has never known freedom in his life and suddenly it is so close that he feels it in his body.
Huck’s guilt about helping Jim escape slavery only emerge as a result of Jim’s use of a hyperbole. In hearing Jim describe his extreme feelings, Huck can better understand his own extreme feelings of angst about helping Jim—as a white child in the pre-Civil War American South, Huck has been taught that helping Black people escape is morally wrong. Going against his “values” makes him also feel trembly and feverish, an experience that shifts over the course of the book as he comes to develop his own moral compass.
Huck narrates the novel in a Pine Country Southern vernacular and, as such, often speaks with exaggerated, hyperbolic language. For example, when Huck reunites with Jim on the raft after escaping a mob of angry townspeople who have been scammed by the duke and the king, he describes his experience as follows:
Jim lit out, and was a-coming for me with both arms spread, he was so full of joy; but when I glimpsed him in the lightning my heart shot up in my mouth and I went overboard backwards; for I forgot he was old King Lear and a drownded A-rab all in one, and it most scared the livers and lights out of me.
The phrases “my heart shot up in my mouth” and “it most scared the livers and lights out of me” are two examples of hyperbole, in that Huck uses exaggerated language to emphasize an extreme internal experience. Though neither of these descriptions is literally true, they capture the extreme fear Huck feels in that moment.
In choosing to highlight Huck’s extremely unsettled reaction in a moment that otherwise would have been a joyful one (Huck and Jim are happy to be reunited and alone on the raft), Twain signals that something is amiss. It is therefore less surprising when Huck and Jim discover that they are not actually going to be free of the duke and the king (or their schemes) when the two con men make it back to the raft just in time. Their attempts to be joyful and free alone together are thwarted yet again.