I can
I k'n
/aɪ kən/Reduction
In real speech
What happens to the sounds
Unstressed can sounds like a short /kən/ — “k'n”. Negative can't keeps its full vowel /kæn(t)/ and the stress, while the t is often silent.
When to use it
The key to understanding: “I k'n go” = I can; “I CAN'T go” = I can't (longer and stressed).
Casual → formal
Slang
I k'n
Neutral
I can
Formal
I am able to
Sound notes
Reduction: unstressed words get squeezed, and their vowels turn into the neutral sound /ə/.