A reader named Alex asked the following question:

“Hello Lisa, I find one of the biggest differences between the British and the American accents is how “can’t” is pronounced which I also find the trickest for us trying to learn the American accent. I just can’t really tell the American “can’t” from the American “can”. So I have to say the British “can’t” instead so as to avoid confusion even though I know it sounds awkward when I am trying to imitate the American accent. Could you please give me some tips on how to cope with it? Thanks so much!”

Here is my answer:
This is a common problem. I discuss this issue in my book “Mastering the American Accent” on page 35. You need to know that negative auxiliaries (such as can’t, won’t, wouldn’t, isn’t, etc) are stressed, but affirmative ones are not. Therefore, because “can’t” is stressed, the vowel “a” is longer than in the word “can.” “Can” is reduced and sounds kind of like “kn.” This reduced vowel is short and neutral (schwa sound).

Practice this:

I kn go. (can)
I caaan’t go. (the phonetic symbol is /ae/ so it’s not actually the British sounding /a/.)

If you only listen for the “t” at the end of the “can’t” you might still be confused since that final “t” is usually held. It’s kind of like a silent, half T.

This is why it’s important for you to know the rules of English word stress and rhythm. Also, following these rules will create a native sounding melody in your speech.

Good luck!