On 14/04/2013, Shriramana Sharma <samj...@gmail.com> wrote: > On Sun, Apr 14, 2013 at 2:32 AM, Christopher Fynn <chris.f...@gmail.com> > wrote:
>> The purpose of having most of these characters there was to facilitate >> conversion between Tibetan and Devanagri scripts. > Well conversion from Tibetan to Devanagari can easily be done even > without these characters -- they only facilitate one-to-one mapping. I agree - but some people thought they should be there for that purpose. (Mind you I've never encountered anyone with the need to actually do this.) Most of these characters were in earlier proposals for Tibetan which mimicked that of Devanagri and the other ISCII derived encodings. They kind of just got left in. There were also proposals to have an invisible root consonant marker - to flag the root consonant in a Tibetan tsheg-bar or syllable. Other proposals wanted to have all the Tibetan consonants encoded + combining super-added RA LA and SA (ra-mgo la-mgo sa-mgo) + subscript YA RA and LA. This would mean having to type (or re-order) these head letters after the base consonant. It might seem to have made Tibetan collation easier - but to get that to work as intended, it would have also been necessary to encode a PREFIX-GA, PREFIX-DA, PREFIX-BA, PREFIX-MA and PREFIX-ACHUNG - all of which would have to logically occur after the root cluster but be re-ordered before for rendering. Anyway all these models completely fall apart as soon as you move away from standard orthography for standard Tibetan words. All assumed Tibetan neatly followed the orthographic rules found in Tibetan grammar books - but this is not the case. First there are different rules as to which letters can be combined with each other when writing Sanskrit and other Indian languages - but there are still rules for this. However these break down when transliterating words from other languages (Chinese, English, etc.) into Tibetan. Next there are some unusual combinations required when writing some other Tibeto-Burmese languages in Tibetan script. Finally some Tibetan texts are full of abbreviations which are written in a way which break all the standard rules of Tibetan orthography and characters are combined in all sorts of weird and wonderful ways. (See: http://www.dzongkha.gov.bt/publications/PDF-publications/Duyig.pdf for some examples.) The encoding model finally adopted for Tibetan simply follows the way Tibetans are taught to spell out combinations - and the way, and order in which, they actually write. After all we were encoding a script the way it is *actually* used - not encoding the rules of Tibetan grammar or rules in books of orthography which tell you how the script is supposed to be used. - Chris
