The great 'Ain't' debate.

[mc2]

I'm from the Ohio Valley, so I've heard some remarkable butchering of the English language. "Ain't" is used all the time. Personally, I don't think it is a word acceptable for 95% of English conversations, but if you do choose to use "ain't," than it is okay. Oddly enough, I know that at one time I used to pronounce "can't" as "cain't," like my Dad. Just a random hypothesis, but perhaps that same pronunciation where you add an "i" to a word that doesn't have it. Anyhow...  

[LaTierra Nik]

http://www.ted.com/index.php/talks/erin_mckean_redefines_the_dictionary.html

This is an interesting talk for word-o-philes such as ourselves, and might actually make you stretch your boundaries a bit. Words have unique uses and even the most banal and made-up words are STILL words... The debate that should rage should be on the topic of "Is this word appropriate for formal writing and proper language?" No, but that does not nullify its uses. For instance, if someone was famously quoted as saying "I ain't gonna do that" then who are you to correct diction on their behalf?

Ain't is a color word, a nippy little brush stroke item and though certainly improper, it should not be discredited as a utility.  

[egginaframe]

Well, it's a word because now it is defined in the dictionary!

But, there are a lot of slang terms out there that are now acceptable. Ain't is on its way up there.  

[Thundurr]

Ain't is a word, it just doesn't have one singular meaning. It can be used as ''am not'', ''have not'', ''has not'', and so on, and so can be used in different contexts.
|:
It's highly informal.

It's a horrible word though.
"Ain't".
Ew.  

[koizumi_riyuu]

It's a word. If it's in the dictionary, it's a word.  

[Houra]

"Ain't" is technically not an abbreviation of "are not", as you said, there is "aren't". And where does the 'i' come from?
"Ain't" is a word, but only as slang, I believe.

And to Koizumi_riyuu, not all things in the dictionary are words. There are suffixex/prefixes, abbreviations, slang terms (which are defined as slang and not words), and acronyms. There are also people and places in some dictionaries.  

[Master Akhekhu Crocell]

I agree with Houra, It's a slang term/word, but only as such. I used to be guilty of saying it when I was younger, but I prefer to say "aren't" instead. The only time I'd time I'd raise my brow at someone using it would be during a formal situation. Slang words to me are words, but I tend to avoid them when possible.

 

[Ithaya]

It's just a slang word.
If you use it in essays then you're insane.
If you use it in speech, then, what the hell, carry on.

It's one of the slang words that doesn't really annoy me that much.
I even use it occasionally, though mainly on Gaia and MSN, not in speech.