Definition and Examples of Negative Contractions

A negative contraction is a  negative verb construction that ends in -'nt.

These are the negative contractions commonly used in speech and in informal writing:

• aren't, isn't, wasn't, weren't
• can't, couldn't, mustn't, shouldn't, won't, wouldn't
• didn't, doesn't, don't
• hasn't, haven't, hadn't

Shan't (the contraction of shall not) is extremely rare in American English, but it can still be heard in British English. Contractions for may not (mayn't) and might not (mightn't) occur infrequently in contemporary English. Except in Hiberno-English (which uses amn't), there is no negative contraction for am, though the nonstandard form ain't is sometimes used in casual speech. 

Examples and Observations

• "'If you shouldn't be defendin' him, then why are you doin' it?'
  "'For a number of reasons,' said Atticus. 'The main one is, if I didn't I couldn't hold up my head in town, I couldn't represent this county in the legislature, I couldn't even tell you or Jem not to do something again.'"
  "'You mean if you didn't defend that man, Jem and I wouldn't have to mind you anymore?'"
  "'That's about right.'"
  (Harper Lee, To Kill a Mockingbird. J.B. Lippincott, 1960)
• Stella: Oh, you can't describe someone you're in love with! Here's a picture of him
  Blanche: An officer?
  Stella: A Master Sergeant in the Engineers' Corps. Those are decorations!
  Blanche: He had those on when you met him?
  Stella: I assure you I wasn't just blinded by all the brass.
  (Tennessee Williams, A Streetcar Named Desire, 1947)
• "I'll say, 'It was an accident Mom . . . a mistake . . . it won't happen again.'
  "And Ralph will say, 'If you hadn't been thinking about that girl this never would have happened.'"
  (Judy Blume, Then Again, Maybe I Won't. Bradbury Press, 1971)
• "I'm getting very deaf. I suppose I don't hear people. Emily's got a bad toe. We shan't be able to start for Wales till the end of the month."
  (John Galsworthy, The Forsyte Saga, 1922)
• "'Don't go to any trouble on my account,' Paul D said.
  "'Bread ain't trouble. The rest I brought back from where I work.'"
  (Toni Morrison, Beloved. Alfred Knopf, 1987)

Negative Contraction and Auxiliary Contraction

• "[N]egative contraction is possible for a much wider range of verbs than the auxiliary (or non-negative) contraction in standard English. Practically every verb (except am) has a form with a contracted negative, whereas auxiliary contraction is only possible for a smaller number of verbs. For this reason, speakers have a choice between negative vs auxiliary contraction for the following verb forms only: is, are; have, has had; will, would; shall, should. Some of the auxiliary contracted forms are ambiguous: he's not is the contracted form of both he is not and he has not (although this use is relatively rare); I'd not be derived from either I had not, I would not or I should not, and you'll not can, at least in principle, be the contracted form of you will not or you shall not.

• "In addition, however, one has to consider different syntactic environments. The distinction between auxiliary and negative contraction is only relevant for declarative sentences. Only here and for those verbs listed above do speakers have a choice between negative contraction, auxiliary contraction and completely uncontracted forms."

(Lieselotte Anderwald, Negation in Non-Standard British English: Gaps, Regularizations, and Asymmetries. Routledge, 2002)

Rogue Contractions

• "Negative contraction is not a possibility with am not (*I amn't), and this causes a difficulty in questions (where inversion does not allow verb contraction). In colloquial English, aren't I is sometimes substituted for the non-existent *amn't I. (The full form am I not is generally avoided.)

I'm naughty aren't I? (conv)
'Aren't I supposed to understand?' (fict)

• "[Ain't] is a very versatile negative contraction, capable of substituting for all negative contractions of be or the auxiliary have:

'There ain't nothing we can do.' (fict) isn't>
'I'm whispering now, ain't I?' (fict) aren't>
I ain't done nothing. (conv) haven't>

• Ain't is common is the conversation of some dialects, and it occurs in representations of speech in writing. However, ain't is widely felt to be nonstandard, and so it is generally avoided in written language, as well as in careful speech."

(Douglas Biber, Susan Conrad, and Geoffrey Leech, Longman Student Grammar of Spoken English. Pearson, 2002)

The Case Against Ain't

• "Long a shibboleth for 20th-century Americans, the negative contraction ain't continues to be Substandard when used unconsciously or unintentionally. It is a word, though, and in Vulgar and some Common use, it replaces are not, is not, am not, has not, and have not in statements. Standard English replaces I ain't with I'm not and the interrogative ain't I (which is often added to statements, e.g., I'm safe, ain't I?) with a choice of somewhat clumsy locutions: am I not? aren't I? or an even more roundabout Isn't that so? . . . The firm rejection of ain't in Standard use is hard to explain, but clearly, Americans have come down hardest on it, and they have made the rejection stick in Standard American English. Consciously jocular uses are acceptable, but using ain't in circumstances that do not suggest deliberate choice may brand you as a speaker of Vulgar English."

(Kenneth G. Wilson, The Columbia Guide to Standard American English. Columbia University Press, 1993)​

Negative Contraction and Be Contraction

• "Whereas for all auxiliary verbs negative contraction (e.g. haven't, hasn't, won't) is vastly preferred over auxiliary contraction (e.g. 've not, 'd not, 'll not), we get the reverse picture for be. Even isn't (12.5%) and aren't (3.5%) are used very rarely in the British Isles, so that the near absence of amn't in standard as well as non-standard varieties is not a striking exception, but simply the tip of the iceberg.
  "The motivation for this striking preference of be-contraction over negative contraction for all other auxiliaries is most likely a cognitive one, namely the extremely low semantic content of be."
  (Bernd Kortmann, Tanja Herrmann, Lukas Pietsch, and Susanne Wagner, Agreement, Gender, Relative Clauses. Walter de Gruyter, 2005)

Negative Contractions and Language Acquisition

• "[C]hildren will use some of the negative contractions prior to their acquisition of the rules for not in the verb phrase. The negative contractions don't, won't, and can't are acquired early and may be used prior to the acquisition of the particular auxiliaries which they represent. Children appear to learn these negative contractions as single morphemes and use them to negate prior to learning the auxiliary plus not."
  (Virginia A. Heidinger, Analyzing Syntax and Semantics: A Self-Instructional Approach for Teachers and Clinicians. Gallaudet University Press, 1984)