Who is speaking in the poem "Hope is the thing with feathers" by Emily Dickinson?

Although it is tempting to attribute the sentiments of this poem or any such poem written in first person to the author herself, readers must take care not to do so. In this case, Emily Dickinson wrote in the first person about hope, personifying it as a bird that "perches in the soul." She concludes by saying that even in the direst circumstances, "in Extremity," the little bird did not need to be fed by the speaker. While we know that Dickinson experienced hardships in her life, notably the death of loved ones, we need not assume that the poet is writing in her own voice. Unless one has direct biographical evidence or a statement from the author that claims the sentiments of the poem as her own, a reader cannot say for certain that the poet is the poem's speaker. 

In fact, Dickinson writes in the first person in a persona that is definitely not herself in "A Narrow Fellow in the Grass." Lines 11 and 12 read, "And when a Boy, and Barefoot - / I more than once at Noon." Dickinson, a woman, was never a boy, yet here she writes in a male persona. In other poems she writes in the voice of a married woman, and she never married. So one cannot assume Dickinson is the "I" in this poem.

The speaker, from the evidence of the poem, is a person who has felt the stirrings of hope within him or her, even "in the chillest land - / And on the strangest Sea." Upon reflection, the speaker realizes that she never had to make an effort to feed that feeling of hope--not even a "Crumb." One might say that the speaker is an optimist--one who experiences hope even in the midst of great adversity.