Answer:
The rhetorical technique used is known as "pathos".
Explanation:
When Yousafzai calls the audience "brothers and sisters" she appeals to the emotions of that audience, as it shows that she sees them as a family, as someone who will understand her feelings and who will sympathize with her words, as families do. By provoking this proximity to the audience, she shows herself to be a trustworthy, friendly and dignified person to be heard.
