Come again is an Informal phrase use to ask the speaker to repeat the same if you did not understand or hear them. Do not use this phrase in a formal context, as it may have an alternate meaning or may be misunderstood.
It is an American slang, short hand for a longer & more polite form, “Could you please repeat what you just said?”
‘say again’ or
‘could you please say that again?’
Example : What did you say, come again?
In British English it is replaced with,
‘I am sorry’
‘pardon me’ or
‘excuse me’
After a meeting with someone, usually we say ‘come again’ rather ‘come back again sometime’.
Even some on say something & don’t believe it was said, you may question, “What did you just say? Come again? I can’t believe, you said that.”
Even though the phrase is grammatically correct, Some American English users may misunderstand it, as having the same used in different connection.
Simple explanation :
To request for repeating the sentence, & not to be used for repeating meeting request.
- American use slang – Come again, say again.
- British English use – I am sorry, pardon me, excuse me.