Teaching characterization consists of identifying what reveals the self in a fictional character's actions, descriptions and dialogue. Since "Flowers for Algernon" is all monologue, the most obvious technique Keyes uses is idiom, or style of speaking. Charlie at first expresses himself like a child -- "I tolld him I imaggen a inkblot . . . I dont think I passd the raw shok test." Misspellings, grammatical misuses and a child-like tone abound; as Charlie's intelligence progresses, Keyes allows him adult vocabulary -- "they think of me as something newly minted in their private treasury" -- and adult tone.
The next matter to note in teaching characterization is how Charlie's tone shifts in complexity with his idiom. He becomes, by turns, resentful of his treatment, emotionally compromised in his relationship with his teacher Alice Kinnian, and, in the novel's later section, fearful and uncertain of the future -- the emotional context is remarkably similar to Mary Shelley's "Frankenstein" creature, thrust unwittingly into a world that rejects him. The tone changes to horror as Charlie realizes that the effects of the operation are diminishing, and he is mentally regressing.
Once the students studying "Flowers for Algernon" realize that tone and idiom shift because they are interrelated, they can map Charlie's emotional and mental progress through the maze of his existence. They should realize the ultimate irony, once Algernon the mouse dies: Charlie has been running life as a lab rat. Once the process begins to reverse itself, Keyes takes away all of Charlie's adult resentments and emotional complexities: "Its easy to have fiends if you let pepul laff at you." The character has gone from happy child to frustrated, frightened adult and back again.
A good class essay for "Flowers for Algernon" is to have students determine what Keyes leaves out of the characterization, such as description; we are free to shape our own Charlie. They can also write of the tale's circular ironies: Charlie is actually closer to his emotions in regression. When he requests flowers for Algernon's grave, he is the picture of loving respect, which he could not show in his intellectually advanced state. Characterization comes full circle.