I'm not sure about variation among users. I know that Braille as used for English (at least in America) has a standard set of short forms (I studied Grade II Braille, as it is called, a bit), including symbols for common letter-combinations, one-letter abbreviations for common words, and sort of "escape symbol"+letter abbreviations for common word-endings and suffixes.The original model for these was that your text processing is done in non-Braille, and on the last leg to a device, you would transcode the regular text to a Braille sequence using a domain and language specific mapping. Having the codes in Unicode allows you to preserve 'final form' and transmit that as needed w/o having to also transmit the text-to-braille mapping(s) that were used to generate the Braille version of the text. (This assumes that the eventual human reader can do 'autodetection'.)
This does not apply to text that have been manually written in or translated to Braille (for a particular language). As I have understood it, writers/transcribers often use(d) peculiar writings, e.g. abbreviations, that would not occur in "normal" text, the "abbreviations" varied from "scribe" to "scribe". I'm not familiar with the details though. Braille can be used also for math and music notation.
B.t.w. Braille often uses "state shifts", e.g. for digits. There is aNot so. There is, indeed, a Braille symbol for "numbers" which, when followed by one or more letters a-j, makes the following string digits instead of letters. There is also, however, a corresponding "letter sign" that can be used to cancel out the effect of the number-shift, or to disambiguate in the case of an isolated symbol that might be confusing otherwise. Both of these, I believe (and can look up) are also used as "escape characters" in making suffix short-forms, and are unambiguous because as letter/number shifts they appear at the beginning of a string, and not in the middle as they would for suffix short-forms (which begs the question of how to encode "a12". I presume that "<lettersign>a<numbersign>ab" would work for the same reason that "<numbersign>ab<lettersign>a" works for "12a").
"digits"
Braille code, followed by one or more codes for the letters a-j (if the
basic
script is Latin) which then stand for 1, ..., 9, 0 (the list is
terminated with
any non-a-j code; but decoding the Braille for e.g. 12a is ambiguous,
IIUC).
~mark
