In Scotland and Northern Ireland, is the contracted form 'amn't' used? In a book, I read such a story? Is it right?

Yes, "amn't" is used there. I don't know whether it's considered standard usage though. The word "ain't" is used in the U.S., but it is not considered proper English.

Thank you. Then how do you pronounce "amn't'? Do we pronounce the letters 'm,' 'n,' and 't' all together?

I don't know, but you're probably right.

The problem is that we have no good way of saying something like this.

I'm smart, am I not?

That's correct. but awkward.

But these are wrong.

I'm smart, ain't I?
and
I'm smart, aren't I?
and
I'm smart, amn't I?

Yes, in Scotland and Northern Ireland, the contracted form "amn't" is indeed used in some local dialects. It functions as a contraction of "am not," similar to how "isn't" is a contraction of "is not" and "aren't" is a contraction of "are not."

However, it's important to note that the usage of "amn't" is not widely recognized or used in standard English or in many other dialects. It's primarily found in specific regional dialects within Scotland and Northern Ireland.

If you came across the use of "amn't" in a book, it could be accurately reflecting the linguistic features of a particular character or the dialect being depicted. It's not a grammatically incorrect form, but rather one that is limited in its usage to certain regions and contexts.

To confirm the accuracy of this information, you can cross-reference with reputable dictionaries, language references, or dialect-specific resources that detail the usage of "amn't" in Scottish and Northern Irish dialects.