Why does my spellcheck say that "could've" isn't a word?

Yes. Spell check is wrong.

Edit: Actually it’s not in the dictionary, so I don’t know if it’s considered standard English. I wouldn’t use it in formal writing, but I assume that everyone would understand that it’s a contraction of “could” and “have”.

Hmm, mine does the same… Maybe because contractions are not considered appropriate in formal letters?

Edit: Ah, wait, it underlines every word (Abiword). OpenOffice underlines no word at all. Lotus Symfony, however (yeah I have that manu word processors :P) highlights should’ve but doesn’t highlight shouldn’t, so it’s not the contraction thingy…

@Vincentt Good thinking…

Cuz it ain’t.

@essieness, yes, it is; or, it is an admissible form. One clue is suggested by Vincentt, having to do with the level of formality or the style you have set in your spellchecker.

The other is that spellcheckers simply do not cover all logical and legitimate forms and extensions of the language. They are a good guide put a poor master. (And of course they won’t help you at all when you’ve written “there” for “their” or even, alas, “per say” for “per se”). Use the Add feature, but use it judiciously. Even if you are positive that you’ve spelled “ecstasy” correctly as “ecstacy,” check the dictionary before you create permanent immunity to the error.

[Edit] Of course you should never use “could’ve” in formal writing, such as in a paper or business letter. Spell it out as “could have.”

“Could’ve” and “would’ve” are colloquial English; acceptable in speech but not correct in formal language. Try putting in “wouldn’t” which is a proper contraction; it should show up in the spell-checker.

@Jeruba – I would expect a spellchecker to contain something as basic as could’ve.

HEY! Firefox highlights Jeruba, spellchecker and Firefox, but it leaves could’ve as-is :)

@janbb
Yes. It’s become more acceptable colloquially but it’s very informal for the written word.

@Vincentt, “could’ve” isn’t basic. Janbb is correct. We recognize it in informal writing, and it could certainly appear in dialogue if you were writing fiction. One of the reasons that a spellchecker is no substitute for a competent human proofreader or editor is that there does have to be a mind behind the judgment in order to assess appropriateness to the situation and the context.

There’s also a little bit of confusion over what it means for a spellchecker to pass something. Does it mean “This is okay to use” or just ”If you’re going to use this, here is the right way to do it”? Should a spellchecker correct “ai’nt” to “ain’t”? Again, you need a human mind.

@Jeruba – yeah but still, if it knows “couldn’t”, I would expect it to also know “could’ve”...

Size of the installed dictionary is going to be a limiting factor. Software creators are interested in supplying a reasonably useful tool and not in being arbiters of the language. Trust me, I edit the writing of software creators. They are not arbiters of the language.

I don’t know. I think it should.

Though sometimes I like to use double contractions like “shouldn’t’ve” and “couldn’t’ve”.

it pisses me off when spellcheck says I spelled “Colour”
wrong…

It certainly is a word (especially if you say so).

Dictionaries aren’t a list of approved words you can use, they are after-the-fact compilations of words people have used. You define the dictionary, the dictionary does not define you!

@ABoyNamedBoobs03, does your spellcheck have settings for U.S. and British spelling?

does it let you get away with “could of”?

I always thought it was a word! Oh no!!!

@phoenyx, a spellchecker would, because they are both real words, even though “could of” as a verb is totally wrong. “Could of” is just a phonetic rendition of “could’ve.”

could of? i thought it meant, ‘could have’

@jenna I think people hear “could’ve” as “could of” and write it that way incorrectly. There are some other examples of words like that, but of course I can’t think of any off the top of my head!

When I said “let you get away with” I was trying to imply that “could of” is incorrect (but a something I seem to be seeing more of on the internet lately).

It is not a word, it is slang, i.e. ghetto-speak.

That’s odd… maybe try ‘coulda’ ?

@ABoyNamedBoobs03 – aargh! Colour is correct! In British… :P