Pronunciations of CAN
This verb is rather special in phonetics because it may be pronounced in different ways, and it is very important to make the difference, or nobody will understand if you say it in the affirmative or in the negative, so here are some explanations and videos.
CAN / CAN'T
The most important thing is to know that the difference between CAN and CAN'T is not the T, because the T usually disappears in a normal conversation. The most important thing to know if it's affirmative or negative is not the T, it is the vowel:
CAN Usually, we don't pronounce the vowel, so it sounds /kn/
CAN'T Usually, we don't pronounce the final T, but we pronounce the vowel in the middle strong and clear. Now, about this vowel, there's a difference between standard British accent and American accent:
Standard British English pronounces this with the vowel in CAR
American English (and some non-standard varieties of BrE) pronounce this with the vowel in CAT
But, as you can see, the real important thing is to pronounce or not to pronounce a vowel between K and N. Here's a video in American English showing you this difference :
SECTION FOR ADVANCED LEARNERS
Now, these other two videos are talking about this in more detail, so if your level is low forget about them because, suddenly, everything will sound very complicated!
On these videos this lady teacher is introducing two new concepts:
1 She talks about emphasis. If for some reason we need or want to put a stress on the affirmative form CAN, then we have to pronounce a vowel there. That vowel, in British or American English, will always be the vowel in CAT . So now, things get a bit more complicated, because we can confuse CAN'T (with no T) with CAN (with emphasis). In real life, of course, that never happens and she's going to explain why. The difference now it's not in the vowel, it's in what happens at the end of the /n/ sound:
2 When we pronounce CAN'T, we usually drop the T, so it disappears, or does it not?. Well, in fact, it's not that the T disappears. What happens is that we change the pronunciation of that T, and instead of pronouncing it with the tip of our tongue, we make something different, we make "a glottal stop". A glottal stop is when you suddenly stop the air flow back in your throat, closing your throat all of a sudden, so the sound of the N gets interrupted quickly and the preceding vowel also gets shorter than usual. She shows on the video how to do this.
one objection to this video lesson
Usually, CAN has no stress (it's unstressed), so it is pronounced quickly and weakly, that's why the vowel between K and N disappears, or almost. Well, it may disappear or it may be pronounced with a Schwa (/ ə / ), which is almost the same. But she makes things much more complicated at this point and she doesn't talk about using a schwa or dropping the vowel altogether. Instead, she talks about two different sounds we can use here, one is the vowel in BELL / e / (which she draws with a different symbol, as you'll see) and the other one is the vowel in SHIP / ɪ /. But she mentions that those two possible vowels are pronounced shorter and weaker than usual. So, sorry if I disagree with her, but if we pronounce those two vowels shorter and weaker than usual, what we get is two slightly different varieties of the vowel Schwa. So it's much more simple to say that when we pronounce CAN, we can either drop the vowel and say /kn/, or we can pronounce it with a schwa / kən /. So for the pronunciation of unstressed CAN, stick to the teachings of the first video (the male teacher) and just drop the vowel, it may be just as simple as that. As for the rest, it's a good video lesson.
And now let's watch the video lesson (in two parts), with explanations and some exercises to practise.