How do you decide which phrase to use when asking people to repeat what they said?

There are many different ways to ask people to repeat what they have just said. For example:

• Huh?
• What?
• Sorry?
• Pardon?
• What's that?
• Say that again, please
• I beg your pardon?

I've ordered them according to my understanding of their level of formality. I'd classify interjection "huh?" as the least formal and phrase "I beg your pardon" as the most formal.

Apart from the formality that you decide to imply, are there any other factors involved when you choose which one of these phrases you will use?

Solution 1:

A more accurate order of formality (least to most) would be:

• Huh?
• What?
• What's that?
• Come again?
• Say that again, please
• Sorry?
• Excuse me?
• Pardon?
• I beg your pardon?

There are of course many more variations on these. A few of these are a lot more common than offers, in particular pardon and sorry which may be used in anything from casual to formal speech. Huh? or even what? are often considered quite rude unless you are speaking casually to a peer/acquaintance.

As mentioned in comments, several of these phrases are more commonly used ironically than directly/literally, most notably "Excuse me?" or "I beg your pardon?" - either is used to express disbelief or indignity.

Solution 2:

I prefer sorry.

Apart from that, I use can you repeat?

Solution 3:

You could also use the more drawn out, but seemingly more formal (to me):

I'm sorry, I missed that (last thing). Could you please repeat yourself?

Solution 4:

A small addition to the earlier answer of Noldorin, for which I agree, is that some phrases may lead to an impression that you did not like what has been said and that you want the speaker to rephrase it or even change it allover.

The following phrases give me that feeling:

• What?
• What's that?
• Come again?
• Say that again, please