There are many different characters in The Phantom Tollbooth. All of these characters have distinct personalities and roles. I think all, or most, of these characters represent something in Milo's life.
"I don't see any reason to learn how to spell. When will it come in use?" questions Milo in the beginning of the book.
Soon after his arrival in "Dictionopolis" Milo runs into a town that's all about words. In this town he learns the importance of words, and spelling. At first, Milo didn't care about language, spelling, and grammer and he soon goes into a land which really stresses the importance of words, how much they say about a person, and how sometimes a little can say a lot.
Out of all the exciting characters Milo meets in Dictionopolis, the Duldroms are probably his least favorite but they are most similar to him. The Duldroms are people who do absolutely nothing all day. Their schedule includes sitting around, daydreaming, sitting and other dull activities. I think these peculiar creatures are exaggerated versions of Milo; Milo admits in the beginning of the book that he does absolutely nothing and find no point whatsoever in doing anything. I think seeing these lifeless people almost terrified Milo and caused him to wonder if actually doing things with your time isn't so useless after all.
Two other characters who represent things in Milo's life are Rhyme and Reason. Although Milo comes to rescue them they are the one's teaching Milo is final life lessons before he leaves the land of Dictionopolis.
Milo starts of as an ignorant character; oblivious to the world around him, friendless, and impatient. There are almost too many characters in this book but almost all of them mean something. Milo needed all these people to put his life back together.
