Final answer:
President Obama uses repetition to emphasize the importance of setting personal educational goals and to resonate with a diverse student audience, encouraging them to take action.
Step-by-step explanation:
President Barack Obama uses repetition in his speech 'Address to America's Schoolchildren' to emphasize the significance of setting and achieving personal educational goals. This rhetorical strategy helps to reinforce the idea and encourages students to take personal responsibility for their learning. By repeating phrases such as 'your goal' and 'maybe you'll decide,' President Obama is encouraging students to take ownership of their education and make proactive choices to ensure their success. By repeatedly addressing different possibilities for goals, the president aims to resonate with a diverse array of student interests and motivations, thereby increasing the likelihood that they will engage with his message and take action.