Final answer:
The stammering in Twain's excerpt reveals the narrator's sudden insecurity when challenged by Mr. Bixby, which is a significant shift from his initial confidence about navigating the river crossing.
Step-by-step explanation:
In Mark Twain's Life on the Mississippi, the narrator's stammering suggests a deep insecurity within Bixby's character. When questioned about the next crossing, the narrator confidently asserts his ability to navigate it.
However, the tone of Mr. Bixby's following inquiry shakes the narrator's confidence, leading him to question his own knowledge and abilities. Twain uses imagery and dialogue to convey the senses of doubt and tension in this interaction. The stammering response, "I—I—don't know," indicates the narrator's shaken self-assurance and highlights the power dynamics between the experienced pilot and the trainee.
Moreover, Twain's reflection on this event, even years later, expresses the lasting emotional impact such moments of insecurity can have.