Why does phoenix keep talking to herself? what do her monologues add to the total portrait of her?

Phoenix Jackson is a character of " A Worn Path" written by Eudora Welty, the author describes her as an old woman with a mission: get to the town to find the medicine that her grandson desperately needs.

Actually, her grandson's throat was not working and nobody is there except Phoenix Jackson and her sick grandson.

She decides to go and on the way to town, she speaks to herself going through various problems till she arrived there. Finally she brings medicine and returns back home.

She is mentally disturbed because of her grandson's throat problem and so she often talks herself on the way to the town an we can say that if Phoenix didn't continue in a running dialogue with herself, the reader wouldn't understand the message and so the story comes from her monologues.

Infact we know about her poor condition of old age, greed for money, love for grandson and courage. Her monologue, her attitude toward life, make clear that her story is a story of unconscious heroism too.