Context is informal writing (i.e. this is not a policy brief where contractions are generally disfavoured; there is no client; there is no style manual to follow). There is, however, a strong inclination to use proper grammar and syntax. Consider:
[ol]
[li]There is a Doper at the bar. [/li]
[li]There’s a Doper at the bar. [/li]
[li]There are Dopers at the bar. [/li]
[li]There’re Dopers on the floor by the bar.[/li][/ol]
Why is the last disfavoured? It’s part of the verbal background, so it’s not unheard. It follows the same pattern as* there’s*—the only thing that changes is the plural.
Further, “they’re” is common, so it doesn’t seem related pronunciation. Consider:
[ol]
[li]He is a Doper; it figures he would be at the bar. [/li]
[li]He’s a Doper; it figures he’d be at the bar. [/li]
[li]They are Dopers; it figures they would be at the bar. [/li]
[li]They’re Dopers; it figures they’d be passed out under the bar.[/li][/ol]
In relaxed (not-severely-formal) spoken speech, “there’re” doesn’t sound much (if any) different from “there are” (as far as I can tell). There’re no benefits to be gained from using this contraction in verbal speech, and no obvious point to using “there’re” in place of “there are” in written text.
ETA: I’m not so sure how common “they’re” is either. Is it? Are there other words also that are commonly contracted with “are”? Most contractions that I can immediately think of involve either “is” or “not”.
There are numerous analogous situations when 's is used but not 're.
When’s he coming? / When’re they coming?
What’s the matter? / What’re the odds?
Who’s at the door? / Who’re at the door?
Partly because in speech, it is easy to elide from a consonant to /s/ or /z/ without the intervening vowel being pronounce, but very hard to go from a consonant to /r/ in the same way, so a speaker generally pronounces “are” but not “is”, obviating the utility of an /are/ contraction.
To be more specific, the repeated “r” in “there’re” is a pronunciation problem. You could say “there are”, with clear enunciation of the vowel “a”. But if you try to pronounce “there’re” in a way that actually sounds like “there’re”, you need to stick in a schwa-type vowel just to be able to say it: “there əre”.
And note the common difficulty many people have with words like “library” and “February”. The specific combination of two "r"s with a vowel between them is a problem. Note that jtur88’s other examples don’t have this, so there’re’n’t any problems there.
I hear “they’re” and “there’re” and “when’re” and “what’re” and similar all the time. Maybe it’s a regional thing, but those are common contractions here.
You don’t see them written very often, though.
I think it’s just habit, really. People aren’t used to seeing those contractions, so they look odd and/or wrong, so no one uses them.
Having thought a little more about this, it seems that a contraction is standard only if the apostrophe does not require a syllable change.
For example, you might write “John’s driving, but Charles is going to walk”. You would not write “Charles’s” because the spoken form requires the part before and after the apostrophe to be separate syllables, generally a no-no. Similarly, “Mary and John are walking, and they’re going to be late.” Contraction only where there is no syllable separation, but not allowed as “John’re”.
A few rare exceptions can be cited, such as “What’re you doing”, but it’s hard to think of any. Also excepted, of course, is a contraction where a complete consonantal phoneme is deleted, like “John’d rather stay home”.
The apostrophe stands for an elision, and is often used when syllables are lost, such as “forecastle” -> “fo’c’sle”.
In this case, the contraction doesn’t involve a syllabic change: “there are” has two, “there’re” also has two (unless the second syllable is elided, which is common, but that could be chalked up to sloppy diction). There are plenty of examples where there is no change, e.g., “isn’t”.
He’s referring to your subsequent parenthetical statement.
Someone who elided the second syllable would sound as if they only said “there” instead of “there’re.” Since neither is usually written down, the spelling is a bit ambiguous.
This is true, but “isn’t” and “is not” do not sound similar, while “there are” and “there’re” do. In fact, both could be pronounced the same way if the vowel in “are” is unaccented and thus reduced to a schwa and “there’re” contains an explicit schwa rather than a vocalic R. (IPA [θɛɹ əɹ], “there urr”). Vocalic R would be “there rrr.”
If I heard “there’re” in someone’s speech that I was transcribing, I would just write “there are,” unless, for some reason, I needed to indicate dialect. I would never do that for “isn’t.”
