Like the writing systems from which it is descended, the Sogdian writing system can be described as an abjad, but it also displays tendencies towards an alphabet. The script consists of 17 consonants, many of which have alternative forms for initial, middle, and final position. As in the Aramaic alphabet, long vowels were commonly written with matres lectionis, the consonants aleph, yodh and waw. However, unlike Aramaic and most abjads, these consonant signs would also sometimes serve to express the short vowels. To disambiguate long vowels from short ones, an additional aleph could be written before the sign denoting the long vowel. The alphabet also includes several diacritics, which were used inconsistently. It is written from right to left, but by the time it had evolved into its child system, the Old Uyghur alphabet, it had been rotated 90 degrees, written vertically in columns from left to right. Voiced and voiceless fricatives are consistently not distinguished in the script. Aramaic logograms also appear in the script, remnants of adapting the Aramaic alphabet to the Sogdian language. These logograms are used mainly for functional words such as pronouns, articles, prepositions, and conjunctions.
Alphabetisation
The Sogdian alphabet was found inscribed in Panjakent, so we can suppose alphabetisation rules - they are the same as in the Aramaic alphabet, but the letter Lāmadh is repeated at the end of the alphabet for values δ, θ.
Transcription
ˀ
β
γ
d
h
w
z
x
ṭ
y
k
l
m
n
s
ˁ
p
c
q
r
š
t
δ
Value
ā̆, ə, ɨ
β, f
γ, x
*
Ø, ā̆
w, ʷ, ū̆, ō̆, ü, ȫ
z, ž, ẓ̌/δʳ
x
*
y, ī̆, ē̆, ɨ, ə, ǟ
k, g
l
m, ṁ
n, ṁ
s
*
p, b, f
č, ǰ, ts
*
r, ʳ, l
š, ṣ̌/θʳ
t, d
δ, θ
Aramaic values
ʔ
B
G
D
H
W
Z
Ḥ
Ṭ
Y
K
L
M
N
S
ʕ
P
Ṣ
Q
R
Š
T
* those letters are not used in Sogdian words.
Varieties
Three main varieties of the Sogdian alphabet developed over time: Early Sogdian, an archaic non-cursive type; the sutra script, a calligraphic script used in Sogdian Buddhist scriptures; and the so-called "Uyghur" cursive script. Early Sogdian dates to the early fourth century C.E., and is characterized by distinct, separated graphemes. The sutra script appears around 500 C.E., while the cursive script develops approximately a century later. The cursive script is thus named because its letters are connected with a base line. Since many letters in the cursive script are extremely similar in form, to the point of being indistinguishable, it is the most difficult to read of the three varieties. As the Sogdian alphabet became more cursive and more stylized, some letters became more difficult to distinguish, or were distinguished only in final position, e.g. n and z.
Child writing systems
The "Uyghur" cursive script eventually developed into the Old Uyghur alphabet, which was used to write the Old Uyghur language. This child script was, however, rotated 90 degrees, written in a vertical direction from top to bottom, but with the first vertical line starting from the left side, not from the right as in Chinese, most probably because the right-to-left direction was used in horizontal writing. The Traditional Mongolian alphabet, being an adaptation of the Old Uyghur alphabet, still uses this kind of vertical writing, as does its more remote descendant Manchu.
In Syriac script, three additional characters were used to represent sounds of Sogdian that were not present in the Syriac language. These were included in Unicode in 2002.Bunz, Carl-Martin Meeting report: 2nd Iranian Unicode Meeting https://www.unicode.org/L2/L2002/02009-iranian.pdf "For the Sogdian script, two possible encoding strategies were discussed. While the soundest solution would consist in providing a code block of its own, a mapping onto the existing Unicode block of Mongolian would be historically also adequate, given that the latter script developed from it."
074D ݍ Syriac Letter Sogdian Zhain
074E ݎ Syriac Letter Sogdian Khaph – compare initial forms ݎ and ܟ
074F ݏ Syriac Letter Sogdian Fe
Old Sogdian and Sogdian were added to the Unicode Standard in June, 2018 with the release of version 11.0. Old Uyghur has been proposed and appears in the SMP Roadmap for possible future inclusion.
Blocks
The Unicode block for Old Sogdian is U+10F00–U+10F2F and contains 40 characters: The Unicode block for Sogdian is U+10F30–U+10F6F and contains 42 characters:
