My dictionary reports that aren't is also an abbreviation for am not, when used in questions.
Is this use of aren't common? If it is common, are there any differences between the different English dialects?
Why aren't I being given a pay raise?
My dictionary reports that aren't is also an abbreviation for am not, when used in questions.
Is this use of aren't common? If it is common, are there any differences between the different English dialects?
Why aren't I being given a pay raise?
Yes, it is common. The little-seen "amn't" does occur in Irish and Scottish English.
There is a good article on this at Wikipedia:
Amn't as a contraction of am not is known from 1618. As the "mn" combination of two nasal consonants is disfavored by many English speakers, the "m" of amn't began to be elided, reflected in writing with the new form an't. Aren't as a contraction for are not first appeared in 1675. In non-rhotic dialects, aren't also began to be represented by an't.
Lower down the page, there are the following sentences:
Aren't as a contraction for am not developed from one pronunciation of an't (which itself developed in part from amn't - see etymology of ain't for further discussion). In non-rhotic dialects, aren't and this pronunciation of an't are homonyms. For reasons that are unclear, the spelling aren't I began to replace an't I in the early part of the twentieth century […].
It's perfectly fine.
In the right dialect you'd also get away with "ain't" (which is the same for first, second and third person, singular and plural, conveniently). But it's widely (UK) considered a bit vulgar.
"..., am I not" tends to give extra stress.
Is it common? Not in my area. It would be considered snobbish to use it. To me, it's unnatural to use are with I.
I would never say: I aren't going to do it. Nor would I use it in a question: Aren't I right? Technically, it's correct but it makes my skin crawl.
Stick with I'm not and Am I not? ... However I'm also in a region where, as @ijw says, one can use ain't without angst.
The original form ‘amn’t I’ as an abbreviation of am I not is first recorded in England in the early 1600s, and remains in use in its original form in Ireland and Scotland. In England the consonant cluster mn was considered difficult and the m was further elided so that it became ‘an’t I?’
But in England another complication arose: as the pronunciation of the letter r was dropped in words like hair and care ‘an’t I?’ sounded like the words aren’t I but with a silent r (ahnt I). So the double abbreviation ‘an’t I? sounded like the ungrammatical ‘aren’t I?’ and then that became the accepted, if errant, version of ‘an’t I’.
Most educated speakers in Ireland still say ‘amn’t I’ although some have adopted the ‘aren’t I’ version.