It is widely known that Shakespeare uses prose for the language spoken by ordinary folk and verse for the high-born, the noble, the members of the upper classes.
The society in which Shakespeare lived was much more hierarchical than contemporary society. Although it was technically possible to rise from lowly origins to become a wealthy owner of land—the ultimate source of social status in Shakespeare's day—most people spent the rest of their lives in the class to which they had been born.
As a man of his time, Shakespeare reflects contemporary class distinctions in his work. He does this, as we have seen, by using prose as the form of speech for common people and verse for the social elite. In A Midsummer Night's Dream, for example, we have Nick Bottom, a humble weaver, speaking in a language with which Shakespeare's audience would've identified:
That will ask some tears in the true
performing of it. If I do it, let the
audience look to their eyes. I will
Powerful words but rendered in prose, in keeping with Bottom's status as an ordinary artisan.
In the same play, we see the use of verse in the lines spoken by Puck in act 2, scene 1:
Thou speakst aright;
I am that merry wanderer of the night.
I jeer to Oberon, and make him smile.
When I a fat and bean-fed horse beguile.
In this excerpt, we can see that there is a clear rhyme scheme, aabb. In most cases, however, Shakespeare uses blank verse, that is to say, verse that doesn't rhyme. Even so, the rhythm of such lines marks them out as verse all the same, therefore appropriate for a noble character.