What’s the straight dope?
There doesn’t appear to be a good one.
“Aren’t I” just sounds awful to me, and I never use that. Besides, it disagrees in number.
What do grammarians say should be the “proper” contraction? Or, maybe they consider all contractions to be improper, so they never considered the question.
Am I not?
Who me?
Ain’t I?
Peace,
mangeorge
I only know two things;
I know what I need to know
And
I know what I want to know
Mangeorge, 2000
I usually use:
“Aren’t I - Mo Fo”?
Haven’t had any grammarian disagree with it so far.
I wouldn’t’ve used ain’t I myself.
'Cause why?
Peace,
mangeorge
“Amn’t I” (two syllables) is technically correct, but people will look at you strangely unless you live in certain parts of Ireland. (“Ain’t” comes from “amn’t”.)
There is no technically correct, formal way. However, that doesn’t much matter, inasmuch as contractions really don’t belong in formal writing to begin with. Use what the people around you use when speaking. Use “Am I not,” or a paraphrase in formal writing.
John W. Kennedy
“Compact is becoming contract; man only earns and pays.”
– Charles Williams
And, regardless of formality, “Aren’t I” is perfectly acceptable conversationally.
Aren’t I would be grammatically incorrect, moreso than ain’t I, because it doesn’t agree in number between the verb and the subject pronoun, whereas ain’t I is correct as to number, but incorrect as to pronounciation.
And, yes, a lot of people say ‘aren’t I?’, but then again, a lot of people use poor English. I have never felt that that was a good reason to use poor English myself. 
“Aren’t I” is always perfectly correct in number as long as we remember to use the royal/editorial “we.” :::sniff:::
 
Tom~
Oh “Aren’t We”. . . You did mean “Aren’t We,” didn’t you guys?
Tom~
Someone enters the room and you politely say: Won’t you sit down? or Will you sit down? Are both correct? assuming that “please” is placed somewhere in each question.
“Aren’t I” is an idiom, and idioms don’t need to conform to the Laws of English Usage.
According to Quirk and Greenbaum:
“‘Aren’t I’ is widely used in British English, but there is no generally accepted contracted form for ‘am not’ in declarative sentences.”
So it’s not bad grammer to use the phrase; there’s no other contraction available other than “ain’t I?”
“East is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does.” – Marx
Read “Sundials” in the new issue of Aboriginal Science Fiction. www.sff.net/people/rothman
Well, since contractions are considered undesirable in formal English, “Am I not?” would be correct.
If you are using informal English, there’s nothing wrong with “Aren’t I?”
“Contracted negative of the first person indicative present.”
The ‘interrogative’ part is moot since the contraction doesn’t work in any voice. And you need to specify ‘indicative’ and ‘present’ if you want to rule out I won’t and I wouldn’t.
I think we should all just start making the contraction and get everyone to use it. I’m making myself clear here, amn’t[sup]1[/sup] I?
Peace.
[sup]1[/sup]Pronounced EM’-ment.
But there’s an acceptable alternative, so it’s not an issue: “I’m not. . . .”
Ahh, but that’s not contracting the negative, but contracting the positive and adding the negative. I amn’t kidding you. 
Peace