Time to brush up on your two-stepping skills because this poem sounds like a dance-off. Or, more specifically, maybe it sounds like the very beginning of one, because things never get too fast-paced or crazy.
First, "Up-Hill" is composed of basically all one and two-syllable words, which roll off the tongue in quick, succinct beats that sound an awful lot like footsteps. Second, the distinct voices of Speaker #1 and Speaker #2 are emphasized by the fact that their lines are different lengths, which we think mirrors the back-and-forth you associate with one of those super-intense dance confrontations. Check it out:
Does the road wind up-hill all the way?
Yes, to the very end. (1-2)
That back and forth of differently-paced lines makes us think that dancing is a great way to think about the conflicting meter and rhythm of "Up-Hill" (check out the "Form and Meter" section if you want more info on that). Just like awesome dancers are usually doing way more with their feet than we as an audience can hear and appreciate, there is a lot more to the sound of "Up-Hill" than what is readily apparent when you hear the poem out loud. The result, on a sonic level, is a clear-cut conversation between two distinct voices, yet housed in one neat little poetic package.