Voice

"Okay, but this is this is how the typewriter interpreted those fleeting impulses raising my fingers to the keys, and those impulses have now died." 

This represents Che's tone. This tone is kind of melancholy or bitter- not exactly a happy way to begin a story. The reader gets the feeling that Che is dissatisfied with the story, or something else.

"But I'll leave you now, with myself, the man I used to be..." 

This also exhibits Guevara's tone. This tone is rather wistful and melancholy. It shows the reader that the book is somewhat of a coming-of-age or transformation story. Che seems to miss the innocence of youth, or the naivete he used to have.