> The ' b g d order is known in traditional Ethiopian circles,

because it

> appears in Psalm 119 (just as it does in the Septuagint).

Evidence of the order appears to be from the alphabetic section names:
"aleif", "beit", "gameil", and "daleit'", simple variants on the
Hebraic letter names (a modern Amharic Bible even includes the Hebrew
letters).* The first syllable of each word follows "a-bei-ga-da".
The "ga" in "gameil" I've certainly seen change forms (gi,ge,g) but
"beit" is a very stable semitic root. So I lean towards the rotated
table as the origin of the word and hebraic scripts for the order.

The "abegede" order is fairly well known, the Ethiopian Orthodox
Church applied it for a time but abandoned it. The order is at times
loosely refered to as "abugida" (as per the table). The "bugida"
(horizontal) aspect of the syllabary wouldn't be applied in "ordering"
though, so I find it misleading.

> It has liturgical uses.

do tell!


/Daniel


*Psalm 119 in UTF-8:
http://www.bible.org/foreign/amharic/psa-119.htm#P2194_104986

Psalm 119 in PDF (with Hebrew) page 66:
http://www.gospelcom.net/ibs/bibles/amharic/pdf/ot/psalms.pdf