A hyphen...................not sure if is this the particular answer you are looking for though
<span>If this was the excerpt: The underlined statement contains the alliteration.
The last of all in the wedding procession of the Rag Doll and the Broom Handle were the Sleepyheads. </span><span><u>They were smiling and glad to be marching but their heads were slimpsing down and their smiles were half fading away and their eyes were half shut or a little more than half shut</u></span>.
They marched with big bowls of soup in front of them and big spoons for eating the soup. They whistled and chuzzled and snozzled the soup and the noise they made
A wide peach had a wide speech for the world
The one of the left with all the colored rings :•)