can't

• ca'n't (obsolete)
• cain't (dialectal, Southern US)

From can +‎ -n't, since 1706^[1] or earlier.^[2]

• enPR: känt, IPA^(key): /kɑːnt/
  • (Received Pronunciation, Southern England, General South African) IPA^(key): [kɑːnt]

    • Audio (Received Pronunciation):

      (file)

  • (Northern England, Wales) IPA^(key): [kɑːnt], [käːnt]
  • (General Australian, New Zealand) IPA^(key): [kɐːnt]

    • Audio (General Australian):

      (file)

  • (India) IPA^(key): [kaːɳʈ]

    • Audio (India):

      (file)

  • (Ireland) IPA^(key): [kaːnt]
  • (some US speakers) IPA^(key): [kɑnt]
  • Rhymes: -ɑːnt
• enPR: kănt, IPA^(key): /kænt/
  • (General American, Canada) IPA^(key): [kænt~kɛənt~keənt], /kæn(ʔ)/

    • Audio (General American):

      (file)

  • (New York City, New Orelans, Philadelphia, Baltimore) IPA^(key): /kɛənt/
  • (Scotland, Northern Ireland) IPA^(key): [käːnt]
  • Homophones: cant, Kant (in some dialects)
  • Rhymes: -ænt
• enPR: kānt, IPA^(key): /keɪnt/
  • (Southern US) IPA^(key): [kʰẽɪ̃nt], [kʰẽɪ̃n(ʔ)]

    • Audio (Southern US):

      (file)

  • Rhymes: -eɪnt

can't

1. Cannot (negative auxiliary^[3]); is unable to; does not have the ability to.

   Antonyms: be able to, can

   I can’t quite get it to work.

   • 2012, BioWare, Mass Effect 3 (Science Fiction), Redwood City: Electronic Arts, →OCLC, PC, scene: Tuchanka:

     Shepard: Mordin, walk away.
     Mordin: Can't do that, Shepard.
     Shepard: I don't have a choice here. Walk away, or I will fire.

2. Is forbidden to; is not permitted to.

   Antonyms: be able to, can, have to, must

   You can’t enter the hall without a ticket.

3. Often followed by be: is logically impossible.

   Antonyms: be able to, can, have to, must

   The butler can’t be the murderer because he was in London that evening.

   • 1750, W[illiam] Ellis, The Country Housewife's Family Companion: Or Profitable Directions for Whatever Relates to the Management and Good Œconomy of the Domestick Concerns of a Country Life, According to the Present Practice of the Country Gentleman's, the Yeoman's, the Farmer's, &c. Wives, in the Counties of Hertford, Bucks, and Other Parts of England: Shewing how Great Savings may be Made in Housekeeping: [...] With Variety of Curious Matters [...] The Whole Founded on Near Thirty Years Experience, London: Printed for James Hodges, at the Looking-glass, facing St. Magnus Church, London-Bridge; and B. Collins, bookseller, at Salisbury, →OCLC, page 157:

     To make Capons […] [S]ome for this Purpoſe make it their Buſineſs after Harveſt-time to go to Markets for buying up Chickens, and between Michaelmas and All-hollantide caponize the Cocks, when they have got large enough to have Stones [i.e., testes] of ſuch a Bigneſs that they may be pulled out; for if they are too little, it can't be done; […]

• Although may and can are synonyms, can’t and mayn’t (including their uncontracted forms) are not, except when used interrogatively. “You can’t have a console” means you must not have a console, but “you mayn’t have a console” means you are not guaranteed to have a console, with the implication that you still may if you do.
• Some US dialects that glottalize the final /t/ in can’t (/kæn(ʔ)/), in order to differentiate can’t from can, pronounce can as /kɛn/ even when stressed.

• couldn't, mayn't, mightn't, oughtn't, shan't, shouldn't, won't, wouldn't

For other translations, see can and not.

• Appendix:English modal verbs
• Appendix:English tag questions

• T-Can, NCTA, anct., TNCA