English contractions are very common in everyday speech. We use them to save time and to show we’re on informal, friendly terms with the person or people we are talking to.
Speech without contractions sounds too formal to most English speakers. It seems stiff or “stuck up," as if the person speaking feels superior.
But contractions are uncommon, and often unacceptable, in formal writing. (That includes business proposals and most academic writing like essays or term papers.)
English contractions can be hard to understand when you fist listen to English. In the U.S. you might hear two young people saying
“Dija see Sally at the game?”
“Nah, she must’ve bin sick—or she kuda gone out with Bill instead. Hey—gotta go now. Seeya soon!”
In correct written English, that would have been: “Did you see Sally at the game?” “No. She must have been sick, or she could have gone out with Bill instead. Hey, (I’ve) got to go now. (I’ll) see you soon!”
For more examples, see (and listen to) this short Voice of America talk. It suggests ways to listen better to everyday conversations. It can help you recognize the grammar you've learned in what people say.
This mock-rap video lists positive contractions. (It might not show on a mobile phone. Most screens are too small.) For his Negative Contraction list see Negative Sentences. It's a funny rap on a bad relationship.
You may have noticed that many contractions have two or more possible meanings. He's= he is OR he has; she'd= she had OR she would, etc. That doesn't bother English speakers because the meaning is usually clear (at least to us!) from the context.
Other contractions are easier. The examples below give the same expression without a contraction in parentheses. (Modals are first, then ‘be’ and the helping verbs ‘have’ and ‘do’)
Incidentally, we almost never say ‘Do you not?’ We would always ask: ‘don’t you…?’
For more examples, see