As Beneatha recounts the event that made her want to be a doctor, she uses a form of alliteration known as sibilance, repeating the /s/ sound multiple times:
We used to take our sleds out in the wintertime and the only hills we had were the ice-covered stone steps of some houses down the street. And we used to fill them with snow and make them smooth and slide down them all day.
As Beneatha recounts the steep snowy stone steps she sledded down, the /s/ sound is overrepresented. This repetition brings to mind a sliding motion that aligns with Beneatha's story about sledding. This sibilance continues as the passage goes on:
… and it was very dangerous, you know … far too steep … and sure enough one day a kid named Rufus came down too fast and hit the sidewalk and we saw his face just split open right there in front of us … And I remember standing there looking at his bloody open face thinking that was the end of Rufus. But the ambulance came and they took him to the hospital and they fixed the broken bones and they sewed it all up … and the next time I saw Rufus he just had a little line down the middle of his face … I never got over that …
The sibilance in this passage highlights both the injury in "split" and the healing of said injury by a doctor in “sewed,” which is ultimately what inspires Beneatha's dream of becoming a doctor. This scene occurs after Walter loses the money that was supposed to go towards Beneatha’s schooling, making this a particularly poignant reflection on the origin of her dream. Considering the role of dreams in the play, the use of alliteration to emphasize Beneatha’s dream in the moment that she proclaims to give it up underscores the emotional low of the play, the moment where all appears to be lost. In fact, both the Langston Hughes poem from which the play's title is derived and the play itself urge one to hold on to their dreams while recognizing how hard that is when faced with adversity. Using alliteration to emphasize Beneatha’s dream of being a doctor in the very moment that this dream seems to become impossible furthers this theme, ] setting the stage for Beneatha’s rededication to her dream in the form of desiring to travel to Africa and serve as a doctor.