Williams wrote "The Dance" about Pieter Greughel's painting, "The Kermess," so he needed to paint the picture with words. There are visual and phonic uses of words that help create this picture. The sounds of the poem capture the dance, the song, and the general atmosphere of this local, peasant celebration. In lines 2-3, the repetition of "round" and "around" reinforce the idea of a circle as if the words are in a circular, repeating pattern. Songs and dances tend to consist of repeated phrases/verses and moves. And since this is likely to be a festival celebrating a patron saint's day (or some other periodic holiday), the idea of circularity and repetition of the celebration adds to that idea as well.
And although this might be a holy day, it is a sensual, uninhibited celebration. Given that this is a painting of peasant life, a celebration would have no room for "proper" behavior. The words describing the music, "squeal" and "blare," are quite blunt; this indicates that the music is loud and boisterous, just as the participants are.
The poem is written in a kind of free, but rhythmic verse. Williams writes it almost in a prose form. This is in keeping with the idea that it is more local, everyday speech; more attune to peasant life. In terms of form, some of the lines run on to subsequent lines (enjambment) and this reinforces the idea of circularity. This is structured like a poem so there is a structure to it, but the enjambment indicates a freedom from that structure. Consider that this is about a holy day, a repeating celebration, but one in which the peasants are partying and are more free than they are during the structure of a usual working day.
There is a rhythm to the phrases "squeal and the blare and the tweedle of bagpipes" and "a bugle and fiddles tipping their bellies" that gives a sing-song quality; an obvious phonic connection to the song and the dancing.
"Kicking and rolling about / the Fair Grounds, swinging their butts," Williams uses plain, visual language (kicking and rolling) to describe the plain and perhaps awkward (therefore realistic) dancing. Using "butts" Williams chose a term that one would not find in an Alexander Pope poem. Williams is clearly sticking to the ideas of real peasant life, using their words to describe the sights and the sounds.
Even though "The Dance" looks more like a paragraph than a poem, there are rhythmic phrases, using stressed and unstressed syllables (feet) which may or may not be contained in one line. One of the phrases that is contained in one line is in line 11. The phrase "prance as they dance" uses assonance (the repetition of a vowel sound) to reinforce the sound of a song or a drum beat. The foot is a choriamb, a metric foot consisting of a stressed-unstressed-unstressed-stressed pattern: "prance as they dance." This also sounds like a musical phrase or a repeating drum beat.