As a non-native speaker, I feel that it is ridiculous that can and can't could sound so similar in American accent.

Just now, I was just listening to a video in which the speaker with an American accent says

Fat cells can't reproduce themselves.

The speaker dragged the word "can't" longer for emphasis, but perhaps as a result, what I heard at first was

Fat cells can reproduce themselves.

Of course from the context I later figured out what he was really saying, but I felt extremely surprised by how these two words which literally mean the opposite could sound so similar in American accent. How is that not affecting American people's daily conversations? As a non-native speaker, is there a way for me to further clarify them when my listeners are confused? (Like when you say "one-eight" to clarify that you were trying to say "eighteen" as opposed to "eighty".)

  • In British English?
    – b.roth
    Commented Feb 18, 2011 at 12:42
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    I agree; I often find it very difficult to distinguish "can" from "can't" in spoken English. This happens to me in British, Australian and American English. Any tips are welcome.
    – CesarGon
    Commented Feb 18, 2011 at 13:19
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    I see no reason for trouble in British English or Australian English: can is pronounced /kæn/, /kɛn/ (as in American English), while can't is pronounced /kaːnt/ (≈"cahnt", listen), an entirely different vowel. Commented Feb 18, 2011 at 13:35
  • @ShreevatsaR: Interesting, thank you. According to @Kosmonaut below, this is not the case in American English, right?
    – CesarGon
    Commented Feb 18, 2011 at 13:40
  • This is the case in Boston and New England in General, many older people who are born and bred in the area say /kaːnt/ (cahnt), instead of /kænt/. Commented Feb 18, 2011 at 17:59

5 Answers 5


I'm a native speaker of American English with Chicago/Ohio influences from my parents and have grown up mostly in the South. Here's how I do it:

I "kin" [can] go tomorrow, or, I "kən" [can] go tomorrow. These two vowel options are not necessary perceived as a binary choice, in other words, they easily blend into a hybrid vowel which is mostly subsumed by the nasal n sound. There is a moderately audible exhalation of air on the K, and once the jaws pulls up from the aɪ of the preceding word, the jaw stays in place. There is practically no vowel sound other than the humming of the n. It's really "kn".

Remember, in English we tend to really "hang out" on (extend) the m and n sounds, it's not like Spanish where the tongue or lips meet precisely, separate, and go on to another open vowel. Especially when the m and n sounds come at the end of words, they are treated practically like closed vowels in English.

Also the prosody of the affirmative phrase would tend to include subtle differences in pitch and emphasis. You'd hear some encouraging uptones, emphasizing "I" with a longer, upswinging tone, say, if one is volunteering oneself from among other people. Or if "tomorrow" is the operative assertion (as opposed to today, or next week) then "mər" of "morrow" is emphasized with a slightly higher (more friendly) pitch. These subtle changes in pitch and the lengthening of certain syllables call attention to the positive intent of the phrase.


I "kæ(n)ʔ" [can't] go tomorrow. There is a more audible exhalation with the K sound. The n sound is more a nasalization of the æ, which vowel also requires a movement of the jaw. In terms of prosody, the "I" is quick, and there is a slight rhythmic emphasis on the syllables "can't", "go" and possibly the "ma:" of "morrow". To keep the pitch quick and low on "morrow", notice the vowel may open out from ər of the previous sentence to a:.

In addition to pronunciation differences, there are usually important clues in the surrounding choice of words, and facial expressions, telling you whether this is an affirmation or a negation.

I can't go tomorrow. [brow furrowed, squinty eye contact with listener]
I can't go tomorrow, but maybe [suggests an alternative].
I can't. [point blank refusal. All the earlier pronunciation qualities apply]
They can't go tomorrow because [explanation given with refusal].
I'm sorry, they can't go. [apology gives it away]
Who told you that? I can't go tomorrow, I have to be at work by 8. [heated refusal with reasons]

Or, [all the following are said with a relaxed, open facial expression-- lifted or neutral eyebrows, and a relaxed jaw and lips]

I can. [upbeat prosody]
I can hardly wait! [expression of enthusiasm]
I can go tomorrow if you want. [makes it a conditional offer]
They can go after they've finished eating. [another conditional affirmation]

These are all personal conversations. In other contexts such as the scientific commentary you reference, there should be other clues:

Fat cells can't reproduce themselves. Fat cells can reproduce themselves.

With the second, positive affirmation, you are either going to hear the humming of the n sound of "can" for longer, with a: for the vowel, if the idea is being emphasized. Or the word will collapse down as I explained earlier, into "kn".

With the negative assertion you will hear more air with the K of "can't". You'll hear the nasally æ(n) sound with a glottal stop at the end.

There will probably be clues in the surrounding comments, as well.

Hope that helps.


The strongest cue for distinguishing these two words is the length of the vowel (in American English at least).

  • The word can has a lengthened vowel
  • can't has a much shorter vowel

On the telephone, where the auditory signal is compressed, exaggerating the length of the vowels ("did you say ca-an or can't?") is how most people distinguish these two words.

(The cause of this vowel length difference is the presence of the voiceless stop /t/ at the end. Even if the /t/ is realized as the glottal stop (which it often is), this has the same effect.)

  • 1
    it's funny because in the case i mentioned above, the speaker actually pronounced "Fat cells CA-AN’T reproduce themselves." for emphasis. and that might be why i was confused.
    – xzhu
    Commented Feb 18, 2011 at 13:35
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    As well as the vowel length, the presence of glottalisation from the /t/ is not just incidental but also a big clue, I would have thought. Commented Feb 18, 2011 at 14:16
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    In a strict phonetic transcription, can't in my dialect is pretty much [kʰæ̃ʔ], which I can imagine would be relatively difficult to distinguish from [kʰæ̃:n], especially if you're looking for a [t]! Commented Feb 18, 2011 at 19:08
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    Wow, as a native (non-linguist) speaker of American English (western), I can't avoid hearing what I think is a /t/ sound at the end of "can't". I guess I sometimes hear a subtle piece of a glottal stop before it, but always a piece of /t/. If I try to remove the t sound, it comes out sounding "Cockney" to me, with the word being truncated and a heavy glottal stop.
    – mgkrebbs
    Commented Feb 19, 2011 at 9:01
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    @Peter Shor: written, patent and beaten (along with mitten, kitten, etc.) all take glottal stop in Standard American English. The pattern is that you get a glottal stop when a /t/ is followed by an unstressed vowel and an /n/, and otherwise you get a flap. I know of a dialect that puts a flap in all contexts (presumably yours), but that pattern is not common in general. (Note also that ridden gets a flap in all dialects, as the n-rule only applies to /t/).
    – Kosmonaut
    Commented Jun 4, 2011 at 3:47

I'm afraid the opposite to what Kosmonaut says applies in the case of British English.

Can rhymes with can (the object), ban, tan, man.

Can't rhymes with car, bar, mar.

  • 4
    It's not as simple as that; British English is itself divided with respect to this pronunciation: virtuallinguist.typepad.com/the_virtual_linguist/2010/05/… Commented Feb 18, 2011 at 15:12
  • @Will, hmm, I agree for grass/'grarse', but I can't (whoops!) think offhand of any British accent where can is pronounced differently than I indicated above. However I think you're right for can't. Which comes back to the OP's question, I guess.
    – Benjol
    Commented Feb 19, 2011 at 9:34
  • Will is right. There is not one way to pronounce these words, in British forms of English. It depends on accents. There are British, regional accents where can and can't are very similar. They don't sound similar in certain, other, regional accents. This is also the case for people without accents and speakers of received pronunciation.
    – Tristan
    Commented Jul 8, 2012 at 22:48
  • However, the Q is about AmE.
    – Kris
    Commented Aug 7, 2014 at 5:40
  • @Kris. It is now :)
    – Benjol
    Commented Aug 7, 2014 at 7:00

In my dialect of American English (mid-western), the unstressed "can" is generally pronounced [ken] or [kən], whereas "can't" is always pronounced with a short "a", as [kænt]. In a stressed position, it's [kæn] vs. [kænt], but the final 't' sound is always aspirated instead of glottal-stopped, making the distinction fairly easy to recognize.


Like you, I think using the context of the "can vs. can't" statement works best. Otherwise (almost always) I can also "hear" the difference in "how the sentence is inflected/pronounced" as well.

the example -

i.e. Usually when spoken, the phrase "I can hear the difference" is tonally pronounced differently and the words are stressed differently from the phrase "I can't hear the difference".

It take some practice, but paying attention to the tonal stress placed on the words "can and can't" should help make things clearer.

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