Aldo Renaldo and the Renegade Alphabet by George M. Johnson, illustrated by Dawn Burn.
Aldo Renaldo has been having trouble with his alphabet, but he finally thinks he knows it and wants to tell Mommy. When he checks one last time, he finds the letters around his walls behaving badly. The K knocks out the O, and the W does cartwheels with the M. He tries to restore order, but cannot. All is not lost, though, because when Mommy enters Aldo uses the new words he has heard from the letters, as he recites the alphabet. When he looks up, the renegade alphabet has restored its proper order.