Here's some paleography stuff, but I haven't worked out one of the symbols and am looking for help :-)
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I don't really need to know what the abbreviations used in the Bedford Psalter page I'm analysing are, since I don't plan to use them when I'm doing calligraphy pieces, but I thought that I'd look up the ones used, for the sake of further understanding.
I've got the Ductus software (thanks Nick!), described at http://www.evellum.com/index.html?ductus/
It reproduces the text of "The Elements of Abbreviation in Medieval Latin Paleography" by Adriano Capelli.
( I also found Capelli's Dictionary of Latin Abbreviations on-line at http://www.hist.msu.ru/Departments/Medieval/Cappelli/ . The explanations are in Italian, which is a great pity, but it does provide the lists of abbreviated letters with their full Latin word counterparts.)
I am jumping around, reading bits and pieces of a rather complicated subject, but this is a little start on it, and hopefully I've interpreted the symbols correctly.
"0.2 All medieval abbreviations, for both Latin and Italian words, can be divided into six categories..... Abbreviation can be indicated by 1. Truncation 2. Contraction 3. Abbreviation marks significant in themselves 4. Abbreviation marks significant in context 5. Superscript letters 6. Conventation signs."
Most of what I've seen in my page of the Bedford Psalter is either truncation or contraction with one possible abbreviation mark significant in itself (at the end)
The following is from "Manuscript Studies - Medieval and Early Modern ... IV.vi.Paleography.Scribal Abbreviations"
http://www.ualberta.ca/~sreimer/ms-course/course/abbrevtn.htm unless otherwise noted:-
"The two most common (and most variable) marks are a macron above a letter or an apostrophe-like curl after or part of a letter; both can mean "some letters are missing" (though in late medieval manuscripts the apostrophe-like mark is frequently otiose: purely decorative, without significance).
I was confused as to whether a macron was a bar or line, as opposed to sometimes being a curved line (tilde) as referred to above, representing an 'a'/syllable containing an 'a'.
Wikipaedia gives
"A macron, from Greek μακρός (makros) meaning "large", is a diacritic ¯ placed over a vowel originally to indicate that the vowel is long. The opposite is a breve ˘, used to indicate a short vowel. These distinctions are usually phonemic."
Never mind the definition, which is a pronunciation based one, at least it tells me that a macron is a bar/line.
A curled macron (a tilde) represents a missing a or a syllable with an a. Assuming that the symbol above is a macron, there aren't any curled macrons in the Bedford Psalter.
From the Bedford Psalter, showing the apostrophe shaped mark and the "9" close together :-
It also is used medially and finally to denote e or er: p'iodic = periodic.
This medieval suspension mark is the origin of the modern apostrophe to indicate missing letters in contractions, as in "don't."
Still to find - an diamond placed above a non-terminal letter,
Capelli says
"1.4 The first truncation sign, a period or dot, is generally placed after the abbreviated word and is still in use today with the same meaning.
But the Bedford Psalter examples have the dot over the word, not at the end :-
I don't know about psaltiu(m?) but egypti would seem to me to be a complete word. So what is the dot doing?
On page 16, Capelli work through the development of a wavy line "3.41 sometimes very pronounced, almost like the letter 'u', is written above the word to indicate the omission of the letter 'r' or a syllable which contains an 'r', such as 're', 'ra', 'ar'. "In many cases, however, this wavy line is used to indicate the letter 'a' or a syllable that ends in 'a'....in this case being a transformation of the letter 'a'.... "In manuscripts of the 14th and 15th centuries, especially those written in the Gothic script, this wavy line develops further into a broken horizontal bar, or two heavy dots closely spaced"
From the Bedford Psalter :
From my reading of Capelli, I am thinking that the first character shown here is a specialised symbol, indicating a specification abbreviation of letters.
On another page of the Bedford Psalter there is
A couple more double dots, indicating endings in an 'a' or a syllable containing an 'a'.
Capelli says
"1.5 Amongst the various abbreviations by truncation, the sigla are easily the most important. They are also the most difficult to interpret since they reproduce only the initial letter of the abbreviated word. Fortunately it is only the most frequently used words and phases that are so abbreviated..... It is generally the majuscule form of the initial letter that at is used, followed by a period."
I think the following paragraph may be relevant to the following weird thing - the "lxx" topped by two dots :-
"1.55 Doubled sigla generally indicated the plural number or the superlative degree, or sometimes also a word in which the letter in the abbreviation occurs two or more times."
I wonder if the 'infinity symbol' (an 8 on it's side) is a Bishop's knot.