The official abbreviation of "am not" is ain. But it is only used in poetry and old English, and it is rarely used now.
Is not can be abbreviated as is, and are not can be abbreviated as are not, but in modern English-in old English and poetry, am not is abbreviated as ain't.
Ain not was originally short for am not. It was originally written as amn't, but later it became ain't because of the problem of pronunciation linking (omitting the previous consonant M and pronouncing only the last consonant N). Obviously, it consists of a be verb am and a negative word not, so in principle it only applies to any abbreviation of am not.
Extended data
Ain not, originally said by a group of illiterate rude people (but not indigenous people) in the southern United States, is becoming more and more common and has been included in various dictionaries.
It started with the abbreviation of am not. At first, it was written as am n' t, but later, due to the problem of pronunciation linking (omitting the previous consonant m and only pronouncing the last consonant n), it became ain 't. Obviously, it consists of a be verb am and a negative word not, so in principle it only applies to any abbreviation of am not.
In Britain, ain generally only uses the working class, such as people who speak London dialect, which is usually considered inappropriate. The middle class and the upper class, as well as Britain in the19th century, are willing to use it in familiar speeches and the education of the upper and middle classes.
It rarely appears in formal writing, and is usually used in more informal written vocabulary, such as the lyrics of popular songs.
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