Can vs. can’t in phonetic pronunciation

Can vs. can’t  in  phonetic pronunciation

Because the “t” in can’t is not clearly pronounced in American English, it sounds similar to can.
How can we determine the difference? When we use the positive form of can, we quickly glide
over can and it is hardly pronounced. Since can is unstressed, it is pronounced \kən\.
• They can come on Friday.
On the other hand, when we use the negative form can't, we tend to stress the fact that it is the
negative form by stressing can't. Since can’t is stressed, it is pronounced \kæn(t)\. Note that the t
may be silent in the nt combination.
• They can't come on Friday .
As you can see from the above example the sentence, "They can't come on Friday" is longer than
"They can come on Friday" because both the modal can't and the verb come are stressed.