Classroom situation: the other person speaks too quickly. A polite request to repeat helps keep the dialogue moving.
Mini-dialogue
¿Puedes repetir más despacio, por favor?
Claro. Lo digo otra vez.
Try this in conversation: “¿Puedes repetir más despacio, por favor?” — “Can you repeat more slowly, please?” Read the mini-dialogue aloud, change one detail and answer in your own words.
Try it yourself
One person says three words; the other asks for a slower repetition. Repeat the activity in a calm conversational tone.