The question tag for ' I am a teacher' is not amn't I, but aren't I in standard english.please explain why?

Answer 1

First, Bruce is correct that there is no such form as "amn't". A form like that is unpronounceable -- and so "am not" led to the contraction "ain't".

But your basic question still stands (with that fix) -- why do people say "aren't I" rather than "ain't I"?

Before I get into why "ain't" is a problem, let me state up front that I believe "aren't I" is perfectly fine colloquial English. Despite appearances, it should NOT be regarded as ungrammatical or "substandard" (much less "atrocious English" as some grammar snobs insist).

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Now about "ain't"

In fact, at one time it was considered quite proper English to say "ain't" in such a context. But it appears that in the 19th century that form became associated with the "lower classes" of London, in the minds of the elite, who began to avoid using it.

It has been suggested that the appearance of the form (in the mouths of lower class people) in the writings of Charles Dickens played a significant role in this.

Actually, this is not the only way "ain't" has been used. Rather, there a number of dialects in which it has been common to use "ain't" not just with the first person, but with others as well -- not just "ain't I"/"I ain't", but "he/she/it ain't" and "you ain't".
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I think the last observation may help explain this whole bit about the use of "aren't I" in colloquial English

Here's why --

There are quite a number of examples in English pf CONTRACTIONS that do not "follow the rules" used for the UN-contracted forms with regard to person and number. Instead, the SAME contracted form may be used with all persons (and sometimes with both singular and plural).

A couple of cases you may have heard
"he don't care"
"There's twenty people at the door!"

Now the first of these is found in dialects that are not currently considered "standard", but which reflect COMMON use in several English dialects spoken by the colonial forebears of these folks. The second is STANDARD for colloquial American English (that is, everyday speech!)

But the same people who use these forms, would say "He does not..." and "There are twenty. . ." when the verb is separate, or is joined to a separate contraction. Thus we say "There aren't twenty people....", using the expected plural verb form.

Also note that part of the reason for using "There's" when what follows is plural is that there IS no alternative contraction that will work (can't say "There're" !) This may help explain some of the other "irregular" uses of contracted forms.

Given this use of "ain't" and "don't" (which were once widely accepted uses) and "there's" (which still is), I think the analogous use of "aren't" for the first person in some instances is not only understandable, but should NOT be rejected ... certainly not in everyday spoken English.
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Now you might not want to use the form for FORMAL English -- but formal isn't all that keen about contractions anyway! Instead, you will be forced either to use the awkward or snobby sounding "am I not?" (and that awkwardness is precisely why I do NOT recommend using it for spoken English). OR you might try to recast what you're saying to completely avoid the problem.

If you really want to avoid it in colloquial English, you might ask a different question that gets at the same point, e.g., "I am a teacher. Isn't that right?" (But this form may have a different connotation from what you wanted.)

Answer 2

According to "Fowler's Modern English Usage", this contraction was originally only used in Scottish and Irish dialect, and was not considered proper English. However, it has crept into general use and is now considered correct.

Answer 3

Well, there is no such word as "amn't." "Ain't" would work, but it is considered illiterate. "Aren't I" is problematic because we wouldn't say "I aren't." Thus, the preferred form, though stilted, is "am I not."

Cheers,
Bruce

Answer 4

"Am not" is contracted as "aren't" -- it's one of those exceptions that make people so fond of the language. :-)