I often notice that instead of "am not" the "aren't" version is used and I wonder if that is truly acceptable. What confuses me is that in school we were taught that the short version of am not is amn't and so this is correct and plain clear but when I see "aren't" I just can't stop thinking that it's a contraction for "are not" and is plain wrong for first person singular. I tried to search some grammar but all they say is that it's correct:
However, for first person pronoun, I, there is no contraction with the verb be + not. (“Amn’t” is not a word in English.) Therefore, in casual speech and writing, English speakers use aren’t, instead, and except in formal situations, this is considered entirely grammatical.
Because of this authoritative connotation, another way of saying “am I not” developed. Virtually all native speakers now use the form “aren’t I”, which is now completely acceptable in any spoken or informal written context.
I also sometimes stumble upon "ain't" but I know that it's very informal and should be avoided at all costs.
Consider the following:
- I am lucky, am I not?
- I am lucky, amn't I?
- I am lucky, aren't I?
- I am lucky, ain't I?
My question is: Can we use "amn't" in regular speech? Is "aren't" informal or formal and is it an exception in grammar?