Zooman Sam by Lois Lowry

word, but
all
words, even the hardest ones. He had read the title
Island Boy
just by looking at it, and "island" was a very hard word, with an "s" that you couldn't even hear.
    He pulled at the end of the little red thread, and it began to unravel. The z disappeared.

    '"Ooman Sam'" Sam read, and laughed aloud.
    "Keep pulling," his mother told him. "It will all disappear and we can throw the zooman suit into the trash."
    But Sam was looking at it. He was seeing something in his mind.
    "Mom," he said, "see between the O and the M? There's a little bit of space there."
    "Mmmmm," his mom replied. She was putting some clean clothes on his chair, for morning. Osh-Kosh overalls and a striped T-shirt. He hadn't worn such ordinary clothes in a long time.
    "There's room for a whole other letter there," Sam said, still examining the place between the second O and the M. "You could put a K there."
    "I could, but why would I?" his mother asked, with a puzzled look.
    "
Because,
" Sam said, feeling excited at his idea, feeling a whole new future starting, feeling the Chief of Wonderfulness feeling, "if you put a K there, and then you put a nice fat B at the beginning, you'd have a whole new word! You'd have a whole new
me!
"
    He handed his mother the crumpled gray suit.
    She stared at him, shaking her head. Then she smiled.

    "Bookman Sam," she said.
    "Bookman Sam," Sam repeated happily.
    "Maybe I can get the gravy stains out," his mother said, and gave him a hug.