Is it Can or Can't?

[bajabero]

I learned from some YouTube channels that the main distinct between the positive (Can) and the negative (Can't) is that the vowel in the positive one is very short. Sometimes it sounds like c'n with almost no vowel. The negative form will sound normally with a very clear vowel sound. Ok,this was not helpful for me in some cases.

Here is one (can) I've been able to understand perfectly:
* In a radio show about health care. When the interviewer said:

FLATOW: Reed Tuckson, let me just, I'm going to direct a question to you, and I'd be very happy if you'd answer, then you can make your point, please. What about - are we going to be creating another class of people who can't afford these devices, who don't have the smartphones and can't get the same sort of medical care as all these people who do have them?

There are two negative (can)s in that segment (it is at 15:50 of the show, you may listen to it here:ht tp://ww w.npr.org/2012/06/01/154148664/can-technology-deliver-better-health-care)

This is ok. I can easily understand it as Flatow's made a slightly long vowel.

But here is another one that I couldn't catch! I thought that the speaker said: (can't) while it was actually positive (can).
It is in one of Obama's speeches can be found here: (13:15 when he said: our union can be perfected)
ht tp://ww w.youtube.com/watch?v=Jll5baCAaQU)

I think the vowel sound in that one was long. That's why I thought it was negative.

Could you please help me with this thing? more information about how to know whether it is positive or it is negative

Thanks a lot

[Rover_KE]

In that clip it's clearly 'can'. He lengthened the vowel slightly for emphasis, though Americans tend to use a longer vowel sound anyway.

There's more difference between the vowel sounds in BrE than there is in AmE.

Compare the two versions of can here.

Now put can't in the search box and listen again.



Rover

[kilfoy114]

It really doesn't matter how long the vowel sound is. That doesn't distinguish the positive from the negative. The part that makes the distinction is obviously the presence or absence of the 't' sound at the end of the word.

As was stated in the previous answer, lengthening the vowel sound puts emphasis on the word.

[5jj]

The part that makes the distinction is obviously the presence or absence of the 't' sound at the end of the word.

Unfortunately that 't' sound may be hard to distinguish in some AmE varieties, especially if the following word begins with a /t/.

[MartinEnglish]

It's obviously stupid to talk about Am or Br English being "better/worse" than each other but I do think in this case the massive difference between can and can't in British English makes sense.
In British English "can't" is the same long sound as "car" thus making it VERY clear, regardless of if you hear the "t" or not.
"I can swim" "I can't swim" - could be pretty vital that I understand you before I push you into the swimming pool!

[birdeen's call]

Fortunately for those Americans whom someone wants to push into deep water, body language, context, intonation and stress can help avoid misunderstandings. I guess that's what makes such a strange homophony viable. But still, misunderstandings do happen.