I have a series of useful phrases from Jukuu, that assist learners in developing conversations and learning new word/phrases. Which of these would be more appropriate for talking to a stranger? Would I choose a different phrase for a doctor or for a family member? If other phrases are more appropriate please let me know.
Will you speak a little more slowly? 请你说得再慢一点，好吗? I am sorry, sir. Can you repeat that more slowly, please? 对不起，请你再说慢点。 I'm sorry, can you repeat that. 对不起，您能重复一下吗？ A: Can you repeat that, please? 甲：请您再说一遍好吗? Sorry, I don't understand. 对不起，我没明白。
EDIT: To clarify this question. Please note that I am looking for the situation where one would use one phrase rather than another.
Examples might be:
Use phrase x when talking to family members (etc.)