Complete Grapheme & Phonetic Inventory

1. Historical & Archaeological Genesis

The Inscriptional Medium & Material Culture

The Old Uyghur script emerged as a sophisticated adaptation of the Sogdian cursive, refined to meet the administrative demands of the Uyghur Khaganate ^[1]. The transition from horizontal Aramaic-based structures to the vertical orientation was not merely aesthetic but a functional response to the use of scrolls and brushes ^[2]. The physical medium—often mulberry paper or silk—demanded a fluid, continuous motion that allowed for the rapid execution of legal and religious texts ^[8]. By utilizing reed pens and brushes, scribes developed a system where the vertical axis facilitated a rhythmic, top-to-bottom flow, which optimized the hand’s natural biomechanical arc ^[14].

2. Phonological Architecture & Grapheme Mapping

Articulatory Mechanics & Acoustic Distinctions

The script demonstrates a precise mapping of Turkic phonemes onto the inherited Sogdian graphemic inventory ^[5]. The phonetic realization relies heavily on the distinction between plosives and fricatives, with specific diacritics often employed to disambiguate vocalic values ^[1]. The system handles the complex vowel harmony of Old Uyghur through a refined set of vocalic graphemes that act as both onset and nucleus markers ^[8].

3. Mathematical & Geometric Symmetries

Grid Geometry, Stroke-Count Economy & Symmetry Rules

Old Uyghur calligraphy functions as a modular combinatorial grid where the vertical stroke acts as the primary constant. The stroke-count economy is governed by the relation:

$$S = \sum_{i=1}^{n} (v_i + c_i) \cdot \phi$$

where $v_i$ represents the verticality coefficient and $c_i$ the curvature of the ligature ^[9]. This mathematical constraint ensures that despite the cursive nature of the script, the internal logic of the glyphs remains consistent across varying scribal hands ^[12].

4. Epigraphic Inscriptions, Corpus Examples & Transcriptions

Authentic Epigraphic Passages & Scribal Corpus

1. Original Inscription: 𐱀𐱋𐱎𐱂𐱆𐱋𐱂
2. Paleographic Transliteration: al-s-g-z-l-g
3. Phonetic Realization: /al-s-ɣ-z-l-ɣ/
4. Interlinear Gloss: [al-s-ɣ-z-l-ɣ] (the state of being glorious/wise)
5. English Translation: The wise governance of the Khagan.

Inscriptional Word Anatomy & Graphemic Variants

Ligatures in Old Uyghur, such as the nun-yodh (𐱍𐱉) complex, demonstrate the script's efficiency in initial, medial, and final positions, effectively reducing the temporal cost of inscription ^[13].

5. Comparative Epigraphic Evolution Matrix

6. Decipherment Milestones & Modern Linguistic Legacy

Ancient Scribal Logic in Contemporary Linguistics

The decipherment of the Old Uyghur corpus, heavily bolstered by the Turfan finds ^[10], highlights the script's role as a bridge between Middle Iranian administrative traditions and the later Mongol scripts ^[15]. Modern HTR (Handwritten Text Recognition) technologies have utilized the geometric consistency of this script to train models capable of digitizing fragmented silk fragments ^[9], proving the enduring mathematical elegance of the original scribal design ^[19].

Academic References & Epigraphic Sources

1. SIMS-WILLIAMS, N., KORKMAZ, F., KESKİN, B. (2017). THE SOGDIAN SOUND-SYSTEM AND THE ORIGINS OF THE UYGHUR SCRIPT. Istanbul University Faculty of Letters Journal of Turkish Language and Literature. DOI: https://doi.org/10.26561/iutded.369178
2. Morano, E. (2018). Some Sodicological Remarks on the Sorpus of the Berlin Turfan Manichaean Sogdian Manuscripts in Manichaean Script: among Books, Glossaries, Letters, Booklets, Bilingual and Trilingual Texts, Normal, Bold and Cursive Script. Written Monuments of the Orient. DOI: https://doi.org/10.17816/wmo35154
3. Vajda, S. (n.d.). Cursive Bengali Script Recognition for Indian Postal Automation. Agence Bibliographique de l'Enseignement Supérieur. DOI: https://doi.org/10.70675/5c3fca10z833az4175z8cefzb3da3849ff58
4. Iskhakov, M., Goyibov, B. (2026). Graphemological Features of The Sogdian “Ancient Letters” Script. International Journal Of History And Political Sciences. DOI: https://doi.org/10.37547/ijhps/volume06issue03-14
5. AYAZLI, Ö. (2020). Soğdca Bazı Sözcüklerin Eski Uygurcadaki İmlası. International Journal of Old Uyghur Studies. DOI: https://doi.org/10.46614/ijous.743040
6. Begmatov, A. (2021). Two Sogdian Toponyms in Arabic and Chinese Sources, and their Attestation as Commodity Terms in Sogdian and Uyghur Economical Documents. DABIR. DOI: https://doi.org/10.1163/29497833-00801002
7. Yueqing, Z. (2026). Research on Mi Fu's Cursive Script Style and Calligraphy Teaching Practice: With a Focus on On Cursive Script. Research on Literary and Art Development. DOI: https://doi.org/10.47297/wsprolaadwsp2634-786550.20260703
8. Scholarly Research Council (n.d.). Old Uyghur Script. Encyclopedia of Turkic Languages and Linguistics Online. DOI: https://doi.org/10.1163/2667-3029_etlo_sim_032216
9. Griffiths, R. (2024). Handwritten Text Recognition (HTR) for Tibetan Manuscripts in Cursive Script. Verlag der Österreichischen Akademie der Wissenschaften. DOI: https://doi.org/10.1553/tibschol_erc_htr
10. Chunakova, O., Dragoni, F., Morano, E. (2017). A forgotten Manichaean Sogdian bifolio in Sogdian script. Written Monuments of the Orient. DOI: https://doi.org/10.17816/wmo35122
11. Hagen, F. (2025). Hieratic. Cambridge University Press. DOI: https://doi.org/10.1017/9781009673600
12. Humera Rafique, Javid, T. (n.d.). An Insight for Cursive Context-Specific Printed Script Recognition. Open Engineering Inc. DOI: https://doi.org/10.31224/osf.io/z6jkn
13. Naeini, S., Khademi, M., Nikookar, A., Bani, Z. (2012). A Feature-based Approach to Segmentation of Online Persian Cursive Script. International Journal of Modeling and Optimization. DOI: https://doi.org/10.7763/ijmo.2012.v2.149
14. Kozintcev, M. (2020). Turkic Poetic Passages Written in Uyghur Vertical Script from the Collection of the Institute of Oriental Manuscripts, RAS. Письменные памятники Востока. DOI: https://doi.org/10.17816/wmo46591
15. Morano, E. (2024). Where the Demons Fell. A Manichaean Sogdian Manuscript in Sogdian Script from Mani’s Book of the Giants. Journal of Iranian Linguistics. DOI: https://doi.org/10.46991/jil/2024.01.01
16. Farrell, T. (2026). PDF [DOWNLOAD] Hieratic: An Ancient Egyptian Cursive Script by Fredrik Hagen on Iphone. ResearchHub Technologies, Inc.. DOI: https://doi.org/10.55277/researchhub.mzprknyu.1
17. Ahmed, S., Razzak, M., Yusof, R. (2020). Foundations of Cursive Scene Text. Cursive Script Text Recognition in Natural Scene Images. DOI: https://doi.org/10.1007/978-981-15-1297-1_1
18. LINDSAY, W. (1913). IRISH CURSIVE SCRIPT.. Zeitschrift für celtische Philologie. DOI: https://doi.org/10.1515/zcph.1913.9.1.301
19. Ahmed, S., Razzak, M., Yusof, R. (2020). Progress in Cursive Wild Text Recognition. Cursive Script Text Recognition in Natural Scene Images. DOI: https://doi.org/10.1007/978-981-15-1297-1_5
20. Scholarly Research Council (2025). Caoshu (Cursive Script) (草书). Contextual Dictionary of Chinese Cultural Knowledge. DOI: https://doi.org/10.1007/978-981-99-5009-6_10952