Contractions

It is a contraction of two words.

To me, it does not quite have the status of contractions such as "I've", "you've", "don't" etc., and does not quite seem like standard English. Even so, it's used in casual writing, and also when writing dialogue, to reflect the common pronunciation of "must have". Do not use it in formal writing.

....just as you should not use "I've", "you've", "don't" etc, in formal writing.

Mister Micawber
....just as you should not use "I've", "you've", "don't" etc, in formal writing.

True, but to me "must've" is even more casual than those other contractions. There are levels of slight formality when I would be happy to use "I've" but would never use "must've".

But contractions are just ways of transcribing native pronunciation. Why grade them?

(from an on-line dictionary:

Contraction

SYNTAX: the phenomenon that two or more elements are pronounced as one. EXAMPLE: ain't is a contraction of is not, wanna of want to.)

Mister MicawberBut contractions are just ways of transcribing native pronunciation. Why grade them?

You don't feel that in writing "must've" is more casual than, say, "I've"?

No, sorry, not at all... it must be another across-the-herring-pond thing.

Perhaps there are personal preferences involved too.

I notice at http://www.onelook.com that there are 15 entries for "I've", 13 for "we've", and 12 each for "you've" and "they've", yet only two for "must've". This is not scientific or conclusive, but does reflect my perception that

Well, if dictionary entries reflect acceptability, how do you account for 15 OneLook entries for "ain't"?

Mister Micawber
Well, if dictionary entries reflect acceptability, how do you account for 15 OneLook entries for "ain't"?

Well, "ain't" is a well known and well established word, even though it's casual and not very good English. "must've", though probably better English than "ain't", seems, when written down, less of a "real word" to me. It