I missed these Ngrams off the last one as I was getting 'Invalid form registration' for some reason.

http://books.google.com/ngrams/graph?content=demon%2Cdaemon%2Cd%C3%A6mon&year_start=1800&year_end=2000&corpus=18&smoothing=3&share=&direct_url=t1%3B%2Cdemon%3B%2Cc0%3B.t1%3B%2Cdaemon%3B%2Cc0%3B.t1%3B%2Cd%C3%A6mon%3B%2Cc0

http://books.google.com/ngrams/graph?content=archaeology%2Carch%C3%A6ology&year_start=1800&year_end=2000&corpus=18&smoothing=3&share=&direct_url=t1%3B%2Carchaeology%3B%2Cc0%3B.t1%3B%2Carch%C3%A6ology%3B%2Cc0

@Chris B - fair enough, but as you say, it is rather a subculture. As I understand, it the 'Dark Materials' series are children's books, and fantasy at that. I'm sure there are lots of words and spellings in Tolkien and Harry Potter, that are not exactly mainstream. As for general usage, faerie hardly shows up on Ngram, and færie not at all. See below for demon / daemon / dæmon.

The use of the ligature may indeed have a 'mediæval feel' to it, and that's fair enough if you're wanting to give your work that kind of atmosphere, but most of us (and I'm talking about BrE speakers) don't even spell medieval with a diphthong these days, let alone a ligature. :)

http://books.google.com/ngrams/graph?content=medi%C3%A6val%2Cmediaeval%2Cmedieval&year_start=1800&year_end=2000&corpus=18&smoothing=3&share=&direct_url=t1%3B%2Cmedi%C3%A6val%3B%2Cc0%3B.t1%3B%2Cmediaeval%3B%2Cc0%3B.t1%3B%2Cmedieval%3B%2Cc0

Finally, I would disagree that the ligature is more common than the diphthong: everything I've seen suggests it's just the opposite: Google Search gives some 14 thousand for færie as opposed to 4 million for faery. And with more commonly-used words which can theoretically be spelt with the ligature (usually in British English), such as foetus / fœtus or archaeology / archæology, the diphthong is overwhelmingly used rather than the ligature. In fact, for both of these words, Oxford Online only lists the spelling with the diphthong, and doesn't even list the spelling with the ligature as a possible variation.

@HS - It seems we can put quite a lot of these inconsistencies down to the Great Vowel Shift, the first stage of which involved two high vowels being diphthongised - /ɪ:/ as in tree started to be pronounced /eɪ/ as in train, and /u:/ as in boot started to be pronounced /aʊ/ as in house. Spellings, however, didn't change.

So it's possible that oe and ae weren't originally pronounced as they are today, but that the changes were part of a general shift, rather than anything specific to those words that had originated from ligatures.

The GVS apparently accounts for a lot of our present-day homophones. Each word in these pairs apparently had a different pronunciation before the GVS:

meet / meat
piece / peace
see / sea
tee / tea

Not all dialects and not all words were equally affected, though. Just think of the way many Scots pronounce food like good and wood rather than mood.

@jayles - it's in the OED - so there's your answer. I notice these are all from 'up'. (well done,by the way, I hadn't thought of doubling the p in up), so how about with some other prepositions?

@HS - I think you are investing me with more expertise than I possess. However, I think if I was creative, my answer might begin something lie this:

I take it you already know
Of tough and bough and cough and dough
Others may stumble, but not you
On hiccough, thorough, laugh, and through.

http://www.wordsmith.org/awad/english2.html

In other words, don't expect English spelling to be phonetic or particularly rational. What surprises me, though, foreign learners don't seem to have big problems with it. Far more problematic for them are things like tense use.

Or how about this - same sound, different spelling:

fairy
hair
prayer
tear
bare
stare

Or another way - same spelling (ae), different sounds - three I think: ay as in day, ee as in seed, igh as in sigh

algae
anaemic
Caesar
encyclopaedia
larvae
maelstrom
minuitiae
paediatrics
phaeton
praesidium
reggae

http://www.morewords.com/contains/ae/

As has been mentioned several times above, "on the morrow" is a very old expression, with the meaning the next day or the day, with nearly twenty instances in the King James Bible. It seems to have lasted after right up to the end of the nineteenth century. You can also find it in later, often in religious texts.

"On the morrow when Makbeth beheld them comming in this sort, he first marvelled what the matter ment, but in the end remembred himselfe that the prophesie which he had heard long before that time, of the comming of Birnane wood to Dunsinane Castell was likelie to be now fulfilled." - The History of Makbeth - reprinted from Holinshed's Chronicle 1577

"Whereat ye know not what shall be on the morrow" - King James Bible, 1611

"And on the Morrow , being the 1 2. day of January, about ten of the Clock, the Queens Majesty, with the Lords and Bishops in Parliament Robes, did ride from the Palace to Westminster-Church" - 1682

"on the morrow the weather proving tolerable fair, the bees went to labour as usual" - 1781

"On the morrow he presented me to the king, who received me very graciously" - 1789

"On the 17th July, 1828, a writ of summons was sued out against the defendant Jenner, returnable on the morrow of All Souls" - 1831

"it is no great contention, since, by her own avowal,
she began to love me on the morrow.
And yet on the morrow very little took place." - Robert Louis Stevenson: The Pavilion on the links - 1880

Given that this expression is well know from the bible and the fact that the use of 'on tomorrow' appears to have strong connections with Afro-American church communities (http://random-idea-english.blogspot.com/2014/01/random-thoughts-about-on-tomorrow.html), I wonder if this is where it has come from.

@Liverwort - Oh, ye of little faith! :) And here's the one for armor-putter-on-er, with multiple '-er's. - http://www.youtube.com/watch?v=EsXZjZL5UrA

I suggest we make a collection of these thingies here:

do-er up-er - mainly Oz and NZ by the look of it - a house (or other thing) that needs doing up
- http://www.google.com/search?hl=en&q=do-upper#hl=en&q=%22do-er-up-er%22

The Marysville Gazette was talking about a "pick-er up- er and pull-er down-er" in 1955, but what it is, I have no idea.

The following each have several Google hits:
throw-er-away-er
break-er-up-er
pick-er-up-er
doer-without-er
talker-downer
jumper-talker-downer (or ledge-talker-downer)
(nose-)looker-downer

You certainly seem to have found a common pattern here, jayles, so I think we can definitely say it's English.

There are a couple of videos at YouTube, both American - the pants-put-er-on-er, and the armor-put-er-on-er, and a few Google hits for taker-off-er. A single 'er' after the preposition makes some sense, but I think the double 'er' was maybe a local variation.

There's also a zipper-up-er, and there's one of these with a double er on Facebook. Others in Google - 'bringer downer', 'setter upper', 'putter downer'. It's just another example of how people, especially children, like to play with language.

There are lots words we use in informal speech we don't use in formal writing. I see no reason not to use them in conversational emails, but they tend to lend themselves more to speech than writing. Some of them are in the dictionary, some not - a thingy, a thingumajig, a whatsit, a whatchacallit, a doodah. There's also a doofah, which I've just seen listed as being similar to thingy, i.e. when you can't remember something's name, but in Scotland at least, it was short for 'do for later', for example a cigarette you put behind your ear 'for later'.

Is it real English? Well the fact that some people say it and other people understand it, and it's not localised to one small group suggests it is real English, if not exactly Standard English (I doubt you'll find it in any dictionary). Is slang real English? I would say of course yes.

I can't find anything at Google Books, so I doubt you'll find this particular structure in grammar books, but I'm sure you'll be able to find something about made-up words like this, and especially how people like to play with words.

@HS - some of these spelling conventions seem to have arrived much later than the words. For example, Online Etymology suggests that it was in fact fetus, not foetus, in Latin. A well-known example is scissors, which started off without the c until a 16th century scholar decided (wrongly as it turned out) that it came from the Latin verb scindere and so added the c.

I was looking at some 17th century English books the other day and was somewhat surprised to come across 'theater' spelt with an 'er' rather than an 're'. After a bit of investigation, I've discovered that the 'er' spellings for theatre, centre and sceptre seem to have been commoner in English books than 're' endings until about the second half of the 17th century. One 17th century dictionary listed only the 'er' endings, and it's not till we come to Johnson's 1755 dictionary that the 'er' endings disappear form dictionaries. And of the examples Johnson quotes, in the originals they are nearly all spelt theater and center, rather than with the 're' endings he cites.

In Shakespeare's First Folio there are seven instances of theater to one of centre, five of theater to one of theatre, and thirty-six of scepter to none for sceptre.

So sometimes what we think of as the original spelling isn't necessarily that original after all. Especially as spelling wasn't really standardised until the eighteenth century. Spenser may have written 'Faerie' in 1590, but about the same time we have several examples of 'fairie, and then 'Shakespeare spelling it 'fairy' in a 1600 edition of Midsummer Night's Dream, although apparently reverting to 'faerie' in the First Folio (1623).

http://random-idea-english.blogspot.com/2014/04/just-how-american-are-origins-of-center.html

@jayles :)