A friend of mine (whose first language isn’t English) recently asked me how to contract “they are”, to which I replied “they’re”. The same person then asked how to contract “there are”, to which I replied “there’re” (I was speaking not writing at the time). I was then asked by said person to show them how to write these contractions, to which I pointed out that we hardly ever use these in written English and, if you ever do, the majority of people will probably tell you they’re (sorry — I mean: “they are”) wrong. I then wondered how many other commonly-spoken-but-rarely-ever-written contractions there’re (sorry, ahem, “there are”) in this crazy language we call English…

Here’s a little (and by no-means complete) list:

• couldn’t’ve — could not have
• hadn’t’ve — had not have
• he’d’ve — he would have
• how’ll — how will
• I’d’ve — I would have
• it’d’ve — it would have
• mightn’t — might not
• mightn’t’ve — might not have
• might’ve — might have
• not’ve — not have
• she’d’ve — she would have
• shouldn’t’ve — should not have
• there’d’ve — there would have
• there’re — there are
• they’d’ve — they would have
• we’d’ve — we would have
• what’re — what are
• what’ve — what have
• where’ve — where have
• who’ve — who have
• why’re — why are
• wouldn’t’ve — would not have
• y’all’d’ve — you all should have / you all could have / you all would have
• you’d’ve — you would have

For a somewhat more complete list of both commonly- and rarely-used English contractions, check out this page on Wikipedia!