OK, as I really can't get my head around when anyone would say either 'This is she' or 'This is her', how about this - which pair sound more natural?

That's her over there. This will be him coming now.
That's she over there. This will be he coming now.

Exactly the same grammatical structure - copular verb with theoretically a subject complement rather than an object - bot who would ever say the latter pair?

I'd never heard of either of these before, but I don't really see why it should be down to any ulterior motive. Perhaps it's a dialectical thing that has come out into the open (my preferred option). Perhaps it started as young people's slang - there are quite a few instances of both expressions on Twitter and Facebook. Quite a few expressions that were considered peculiar to my generation at the time are now part of the standard language ('hassle', 'hype' etc).

There are a few examples of 'I have no intention on + -ing' at Google Books, starting about 2000, all American as far as I can see, and mainly in self-published books.

'What do you make to' on the other hand seems to be specifically British. Nothing in Google Books, but:

'What do you make to the show so far' - Rob Leigh, The Mirror, 2 days ago

'What do you make to the 'Magic and Sparkle' ad? - The Daily Record, Nov 2103

'Thanks for that, what do you make to the leather seats on these Omnicities?' - Arriva North East

'What do you think to motorway service stations?' - Apparently from the script of 'Endeavour', ITV's prequel to Inspector Morse

A question to readers on a BBC forum (2007) - 'Id like to hear your thoughts on Thierry Henrys start in Spain ... what do you make to his performances to date?' - got thirteen responses, but none mentioned the grammar.

And a couple from Sky Sports on Twitter and Facebook.

I wonder if it's a Northern English thing, perhaps.

HS - I would reword one of your statements - it's you who has the age old debate about different from/to - what Fowler called 'a superstition'. In British dictionaries, including the OED, there is no debate, although Oxford Online while defending it admits it is 'disliked by traditionalists'. In British English 'different to' is fine, and has a noble literary history (Fielding, Smollett, Austen, two of the Brontés, Thackeray, Dickens) (and me, of course!) - and as you say it's 'age old', so it's hardly creeping in - in fact it was probably used more in the nineteenth century than it is now. :)

http://random-idea-english.blogspot.com/2014/01/different-to-revisited.html

I really don't think there's any difference per se between un- and dis-, although with certain words they may have taken on separate meanings. Relatively few words take a dis- prefix, and most of those are hardly ever used with un-.

disloyal, disrespectful, discontented, disoriented, disobedient

Meanwhile no doubt thousands of words can take un-, or its variations in-, il- and im-, the vast majority of which are never used with dis-. Etymology might have something to do with it: un- is from Old English, dis- from Latin.

In the very few cases where there are pairs, I think you have take them individually rather than applying an overall principle.

dissatisfied / unsatisfied - here dis- is the simple negative, unsatisfied suggests what was hoped for wasn't achieved

disorganised / unorganised - they are very similar, but here it is un- that is a simple lack of organisation, while dis- implies criticism, of something perhaps rather chaotic.

The hot potato, of course, is disinterested and uninterested, and many people would agree with what Janet has said, and that is certainly how I'd use them. But it hasn't always been so; in fact originally it was just the opposite: this is from the Online Etymology Dictionary:

disinterested - "1610s, "unconcerned," the sense we now would ascribe to uninterested, with the sense of "impartial" going to disinteressed (c.1600). See dis- + interest. Modern sense of disinterested is first attested 1650s. As things now stand, disinterested means "free from personal bias," while uninterested means "caring nothing for the matter in question." Related: Disinterestedly; disinterestedness."

uninterested - 1640s, "unbiased," from un- (1) "not" + past participle of interest (v.). It later meant "disinterested" (1660s); sense of "unconcerned, indifferent" is recorded from 1771. This is the correct word for what often is miscalled disinterested.

Which confirms my suspicion that the difference between dis- and un- is due as much to fashion and collocation as any deep semantic difference.

@jayles - Of course I agree that 'gotten' is now American usage, but a lot of words and expressions thought to be American are of British origin. For example I've written on my blog about tidbit, which was the original form of the word in England, and only changed to titbit in Britain around the end of the eighteenth century. Fall (for Autumn) also apparently originated in England. And even the spellings 'theater' and 'center' seem to have been more popular than their -re equivalents in Elizabethan England, especially in Shakespeare.

Conversely, some of the expressions and idioms we use every day without thinking about originated in America, yet we never think of them as Americanisms.

I tend not to use Americanisms myself (which is standard style practice in British newspapers), and I quite understand why Americans might equally want to avoid Britishisms. But we need to be very careful before labelling things as Americanisms, especially, as many are simpler older forms of English. We all like what we are used to of course, but what I have absolutely no time for is people on either side of the Atlantic who think their form of the language is somehow superior to the other.

I think you'll also find that Murphy talks of American English rather than Americanisms, just like the OALD lists gotten as North American usage. For me an Americanism tends to mean something of American origin that has been adopted into British (or other) English, just as Britishism is often used to indicate something of British origin being used by some Americans (Downton Abbey and Harry Potter have a lot to answer for, apparently).

As for your second comment, I think the answer may lie elsewhere. It seems that Old English had a perfect construction with habben, but its use was very limited. Its modern uses really started in Middle English. Shakespeare and The King James Bible, both published just as the first settlers were setting out to America, are full of present perfect:

Shakespeare First Folio:

Thou hast howl'd away twelue winters
hast thou forgot the fowle Witch Sycorax?

KJV

Behold, to me thou hast given no seed
And they said, So do, as thou hast said.

I've always assumed that past simple is often used in American English where we would use present perfect, because of the influence of other languages, for example Yiddish. However I think I've read somewhere that the use of present perfect in Britain is still increasing, so it well could be that we use it rather more these days than a couple of hundred years ago.

@Orion - so now we know how good you are put downs, how about something constructive? Or perhaps that really is all you can say.

@Patricia Davies - gotten is a very old English word, and is listed as the past participle of get in Johnson's Dictionary of 1755. Its use by Americans has nothing to do with German. They kept it when British English dropped it in the 18th century, that's all. But let's not let a little fact like that get in the way of your prejudice. And I'm British, by the way.

http://johnsonsdictionaryonline.com/?page_id=7070&i=925

"And I say no more, but that (they say) is not gotten without consent of both sides" - Sir Philip Sidney - The Countesse of Pembrokes Arcadia - 1590

"When thou wer't King: who trauelling towards Yorke,
With much adoo, at length haue gotten leaue
To looke vpon my (sometimes Royall) masters face." - William Shakespeare - Richard II, First Folio 1623

Not to mention 17 instances in "The Workes of Sir Thomas More Knyght" 1557.

Personally I never, ever use it, obliged covering both meanings - duty, and expressing gratitude, especially in BrE.

It is certainly more common in American books than in British ones (it is considered very formal in BrE):

http://books.google.com/ngrams/graph?content=obligated%3Aeng_us_2012%2Cobliged%3Aeng_us_2012%2Cobligated%3Aeng_gb_2012%2Cobliged%3Aeng_gb_2012%2C&year_start=1940&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Cobligated%3Aeng_us_2012%3B%2Cc0%3B.t1%3B%2Cobliged%3Aeng_us_2012%3B%2Cc0%3B.t1%3B%2Cobligated%3Aeng_gb_2012%3B%2Cc0%3B.t1%3B%2Cobliged%3Aeng_gb_2012%3B%2Cc0

But, its origins seem to be British alright. And it's older than the OED's citation of Pamela (1741), appearing in Nathan Baileys's Dictionarium Britannicum of 1730, and in 'The four years voyages of capt. George Roberts', co-authored by Daniel Defoe, in 1726.

In fact we can beat the OED by some thirty years: this is from 1714 - "and I, as in Conscience bound, shall always own my self highly Obligated to you for the same, and acknowledge my self, Gentlemen" = Pax in Crumena, Thomas Rands, London 1714.

http://books.google.pl/books?id=NcEUAAAAQAAJ&pg=PP8&dq=obligated&hl=en&sa=X&ei=AeRcU57_GY-A7QauloHAAw&ved=0CEYQ6AEwBA#v=onepage&q=obligated&f=false

@Bob Foster - Being Scottish, where it is also used in court, I have no objection to 'pled', indeed rather like it. But on a point of information, or however you lawyers put it, although it may have a King James Bible sound, it doesn't actually appear in the KJV, whereas 'pleaded' does, three times. :)

@jayles - OK, but I'd still be very wary of getting too dependent on them, which is no doubt what a lot of people do nowadays. Much better that somebody has a good grounding in spelling. Their best use, as far as I'm concerned, is catching typos. And they won't correct you if you use a wrong but correctly spelt word, for example. According to standard spell checkers the following is absolutely OK:

I have a spelling checker
It came with my PC
It plane lee marks four my revue
Miss steaks aye knot sea

Eye ran this poem threw it
Your sure reel glad two no
Its vary polished in it's weigh
My checker tolled me sew

Even Google Docs, which has contextual checking, only suggests one change. Spell checkers have their uses, but I'd be very suspicious of relying on them. Especially for a non-native speaker. Much, much better use a dictionary.

@Jonahan Bingham - definitely two Books of Mormon. It's the book you've got two of, not Mormons. From various books at Google Books:

"We were there an hour and a half signing autographs and giving out Books of Mormon."
"As I mentioned, I was carrying several Books of Mormon around with me"
"The following year, all the Books of Mormon had been given out."

Most references to "Book of Mormons" are to one, but admittedly there are these two:

"Along with our scriptures and regular teaching materials was an unusually large amount of Book of Mormons. We each had five."

"'Ive got mountains of Book of Mormons, I've read it so many times that I can quote half the book, I know the story better than they do, I've read it more times than they have, and yet, still they persist in bringing me more Book of Mormons "

But they don't exactly come from the highest of literature.

Similar story for "The Book of Common Prayer". From the Christian Observer:

"In the course of the year, the Society for promoting Christian Knowledge has distributed to its members and the public 54,896 Bibles, 75,547 Testaments and Psalters, 146,668 Books of Common Prayer"

"hath caused the books of Common Prayer to be newly printed," - William Cobbett