Seals showing the Indus script, an ancient undeciphered script
Undeciphered writing systems are proposed writing systems for which no decipherment has achieved broad acceptance in the specialist literature.[1] While most examples are ancient, a small number are medieval or modern.[1] In some cases the evidence is too limited to determine whether the marks represent a true writing system, a form of proto-writing, or a set of non-linguistic symbols; modern artistic traditions such as asemic writing likewise imitate the appearance of writing while intentionally withholding stable linguistic meaning.[2]
Difficulties in decipherment commonly arise from one or more of the following: the absence of bilingual texts or other external "anchors" (such as securely identifiable names or dates); uncertain or unknown underlying languages (including possible language isolates); small corpora; and damage or loss of archaeological context needed to test proposed readings against use and genre.[1] In some corpora, an additional difficulty is uncertainty over whether the signs constitute writing at all (as has often been argued for the Vinča symbols).[3]
Various decipherment claims have been proposed for several items listed here (including the Indus script, the Phaistos Disc, and the Isthmian/Epi-Olmec script), but these proposals remain disputed and have not achieved broad acceptance in the scholarly literature unless otherwise noted.[4][5]
Inclusion criteria
This list includes writing systems and sign systems that are commonly described in reliable secondary sources as undeciphered, not fully deciphered, or of uncertain decipherment. Items of disputed authenticity or disputed status as writing are explicitly identified as such.
Proto-writing
Certain forms of proto-writing remain undeciphered and, because of limited evidence and uncertain linguistic affiliation, may never be deciphered.
Sawveh – Guangxi, China; reported as possible proto-writing or writing in some local traditions and secondary sources; status as a historical writing system is uncertain.[12]
Jiahu symbols
Banpo symbols
Longshan symbols
Sawveh
Neolithic signs in Europe
Vinča symbols – Neolithic Europe (Central and Southeastern Europe), c.4500– c.4000 BCE. Often treated as proto-writing or symbolic marks rather than confirmed writing.[13][14]
Megalithic graffiti symbols – c.1000 BCE– c.300 CE; proposed as possible writing and sometimes hypothesized as related to the Indus tradition, though this remains debated.[17]
Singapore Stone – fragment of a sandstone slab inscribed with an ancient Southeast Asian script, possibly Old Javanese or Sanskrit; at least 13th century, possibly as early as 10th–11th century.
Kushan script – c.2nd century BCE– c.7th century CE; partially deciphered, with recent proposals identifying a substantial portion of the sign inventory and phonetic values in the scholarly literature.[20]
Issyk inscription
European scripts
Page 32 of the Voynich manuscript, a medieval manuscript written with an undeciphered writing system
Linear A – c.1800– c.1450 BCE; the sign values are often transcribed using correspondences with Linear B, but the underlying language remains unknown and most texts are not understood.[24]
Phaistos Disc – c.1850– c.1300 BCE; no consensus decipherment, though numerous proposals exist.[25][26]
Paleohispanic scripts – several scripts are partly deciphered (sign values largely known), but many inscriptions and underlying languages remain only partly understood; inclusion and degree of decipherment vary by script.
An inscription in the Pisa Baptistery – a short medieval religious inscription attested in Tuscany; the script/language and interpretation remain debated in the literature.[31]
The Starving of Saqqara – a privately held sculpture claimed to be ancient and bearing an unidentified inscription; provenance and authenticity have been questioned, and the markings are not securely established as an ancient writing system.[32]
Wadi el-Hol inscriptions – Egypt; early alphabetic inscriptions (often dated to the late Middle Kingdom, roughly early 2nd millennium BCE) with proposed readings but no universally accepted full decipherment; frequently discussed in relation to Proto-Sinaitic script.[33][34]
Ancient inscriptions in Somalia – inscriptions reported on Taalo Tiiriyaad structures; independent archaeological verification and interpretation vary in the literature.[35]
American scripts
Andean region
Quipu – Knotted-cord recording devices used in the Inca Empire and by several earlier Andean societies such as the Wari. Possible Proto-Quipus have been found in Paracas and Caral-Supe, though these remain controversial. Quipus continued to be used in certain regions during the early colonial period and, in limited contexts, into the modern era. They are widely accepted as record-keeping devices; whether they constitute "writing" (and what kind) remains debated. Some recent scholarship argues that particular colonial-period quipu assemblages display features consistent with logosyllabic encoding and proposes tentative readings of specific elements; however, these claims remain controversial and do not represent a broadly accepted decipherment.[36] In another case, six early colonial quipus from the Santa Valley, Peru, have been correlated with a contemporaneous Spanish administrative document, making the connection a possible test case for linking quipus to alphabetic texts.[37][38]
Quipu
Mesoamerica
Olmec hieroglyphs – c.1000– c.400 BCE; sometimes proposed as a "mother script" in broader origin theories, though the evidence and relationships remain debated.[39]
Zapotec hieroglyphs – c.500 BCE– c.800 CE; often described as logosyllabic, with varying degrees of interpretation.[40]
Ñuiñe hieroglyphs – c.400– c.800 CE; similar to Zapotec and possibly an offshoot in the Mixteca Baja; often described as logosyllabic.[41]
Izapan hieroglyphs – Late Preclassic; often proposed as related to Isthmian traditions and later Lowland Maya developments; status remains uncertain.[43]
Teotihuacan hieroglyphs – c.100 BCE– c.700 CE; sometimes described as partially logosyllabary and partially a pictography; its relationship to earlier traditions is debated. Descendants include the Mixteca-Puebla Postclassic tradition.[44]
Classic Gulf Coast hieroglyphs – Early Classic to Early Postclassic; often discussed as related to central Mexican traditions.[45]
Cotzumalhuapa hieroglyphs – c.0– c.1000 CE; sometimes discussed as influenced by Teotihuacan and Lowland Maya traditions; seemingly of autonomous local development, though ultimately related to all other mesoamerican writing systems. Interpretation remains limited.[46]
Epiclassic/Early Postclassic hieroglyphs of Xochicalco, Cacaxtla, Teotenango, Tula and Chichén Itzá – generally treated as part of broader regional glyphic traditions; many elements remain only partially understood. Intermediary between the Teotihuacan Classic Period hieroglyphs and their Mixteca-Puebla descendants of the Middle and Late Postclassic.[47][48]
Many Mesoamerican glyphic traditions remain only partly understood, with the Classic/Lowland Maya script being the best-attested and most extensively deciphered. Other regional traditions (including those often grouped under "Mixteca-Puebla" or pictorial-historical codex traditions ultimately descended from the Teotihuacan tradition, most notably represented by Aztec hieroglyphs and Mixtec hieroglyphs) have been interpreted in the literature to varying extents, but are not universally recognised as a writing system, with some researchers considering it a mostly non-linguistic form of expression.[49] Yet, in recent years new research has appeared confirming the existence of logosyllabic elements ("glyphs") intermixed with pictorial images.[50][41] Nevertheless, new approaches have emerged, integrating the pictorial images as key in the linguistic interpretation of all elements in the codices, alongside the logograms and phonograms. These pictorial images would represent greater units of meaning, namely semantograms, also called embedded meanings, than a lexeme (logograms) or a sound (phonogram) which would become of paramount importance to achieve a coherent linguistic message in the codices.[51] Thus, Mixteca-Puebla writing would constitute a form of non-linear writing.
La Venta Stele 19
Olmec colossal head in La Venta (possible name glyph on forehead)
Zapotec script
Isthmian/Epi-Olmec inscription
Izapan tradition (Tak'alik Ab'aj)
Cotzumalhuapa tradition
Oceanian scripts
Kōhau Rongorongo – Rapa Nui. Attested by the 19th century; often hypothesized to encode language but remains undeciphered.[52]
Kōhau Rongorongo
Non writing systems
False writing systems are glyphs that appear to be writing but are not. False writing cannot be deciphered because it has no stable semantic meaning. This includes many forms of asemic writing created for artistic purposes. A prominent example is the Codex Seraphinianus.
Another related concept is that of undeciphered cryptograms or cipher messages. These are not writing systems per se, but enciphered forms of texts written in known systems. Some have become famous and are listed in list of ciphertexts.
References
123Adiego, Ignasi-Xavier (2024). "Deciphering a Writing System: Luck, Intuition, or Method?". In Ferrara, Silvia; Montecchi, Barbara; Valério, Miguel (eds.). Writing from Invention to Decipherment. Oxford University Press. pp.107–139. doi:10.1093/oso/9780198908746.003.0007. Retrieved 2026-02-07.
↑Schwenger, Peter (2019). Asemic: The Art of Writing. University of Minnesota Press. ISBN978-1-5179-0697-9. Retrieved 2026-02-07.
↑Lazarovici, Gheorghe; Merlini, Marco (2016). "Tărtăria Tablets: The Latest Evidence in an Archaeological Thriller". In Nikolova, Lolita (ed.). Western-Pontic Culture Ambience and Pattern: In Memory of Eugen Comsa. Warsaw, Poland: De Gruyter Open Poland. pp.53–142.
12Kenoyer, J. M. (2006). "The Origin, Context and Function of the Indus Script: Recent Insights from Harappa". In Osada, Toshiki (ed.). Proceedings of the Pre-symposium and the 7th ESCA Harvard–Kyoto Roundtable(PDF). Kyoto: Research Institute for Humanity and Nature. pp.9–27. Retrieved 2026-02-07.
↑Baldacci, Giorgia (2024). "The Phaistos Disc: Placing an Enigmatic Artefact in its Cultural Context". In Ferrara, Silvia; Montecchi, Barbara; Valério, Miguel (eds.). Writing from Invention to Decipherment. Oxford University Press. pp.155–170. doi:10.1093/oso/9780198908746.003.0009. Retrieved 2026-02-07.
↑Zhang, Juzhong; Cui, Qilong (2013). "The Jiahu Site in the Huai River Area". In Underhill, Anne P. (ed.). A Companion to Chinese Archaeology. John Wiley & Sons. p.248. ISBN978-1-118-32578-0.
↑Demattè, Paola (2022). "Early and Middle Neolithic Signs to the Fourth Millennium BCE". The Origins of Chinese Writing. Oxford University Press. pp.99–148. doi:10.1093/oso/9780197635766.003.0005. ISBN9780197635766.
↑Woon, Wee Lee (1987). 漢字的原始和演變[Chinese Writing: Its Origin and Evolution] (in Chinese). Macau: University of East Asia. pp.275–276.
↑Qiu, Xigui (2000) [1988]. Chinese Writing. Translated by Mattos, Gilbert L.; Norman, Jerry. Berkeley: Society for the Study of Early China and The Institute of East Asian Studies, University of California. p.33. ISBN978-1-55729-071-7.
↑Tan, Shengmin (2003). 壮泰民族传统文化比较研究[A Comprehensive Comparative Study on Zhuang and Thai Nationalities' Traditional Culture] (in Chinese). Vol.II. Guangxi People's Publishing House. pp.798–799. ISBN978-7-219-04915-0.
↑Liang, Tingwang (2000). 壮族文化概论[Overview of the Culture of the Zhuang People] (in Chinese). Guangxi Educational Publishing House. pp.496–498. ISBN978-7-5435-2992-2.
12Encyclopedia of the Zhuang Ethnicity Editorial Committee (April 1993). "本源书" [Sawgoek]. 壮族百科辞典[Encyclopedia of the Zhuang Ethnicity] (in Chinese). Guangxi People's Publishing House. ISBN978-7-219-02476-8.
↑Lazarovici, Gheorghe; Merlini, Marco (2016). "Tărtăria Tablets: The Latest Evidence in an Archaeological Thriller". In Nikolova, Lolita (ed.). Western-Pontic Culture Ambience and Pattern: In Memory of Eugen Comsa. Warsaw, Poland: De Gruyter Open Poland. pp.53–142.
↑Shinde, Vasant; Willis, Rick J. (2014). "A New Type of Inscribed Copper Plate from Indus Valley (Harappan) Civilisation"(PDF). Ancient Asia. 5. doi:10.5334/aa.12317.
↑Bryant, Edwin Francis (2001). The Quest for the Origins of Vedic Culture: The Indo-Aryan Migration Debate. Oxford University Press. p.178. doi:10.1093/0195137779.001.0001. ISBN978-0-19-513777-4.
↑Lal, B. B. (1962). "From the Megalithic to Harappa: Tracing Back the Graffiti on the Pottery". Ancient India: Bulletin of the Archaeological Survey of India. 16: 21–24.
↑Yeganeh, Sepideh Jamshidi; Holakooei, Parviz; Nokandeh, Jebrael; Piran, Sedigheh; Dahl, Jacob L. (2025). "Complexity of proto-elamite administration system: Insights from compositional data from sealings and tablets". Journal of Archaeological Science: Reports. 61 104973. Bibcode:2025JArSR..61j4973J. doi:10.1016/j.jasrep.2025.104973.
↑Waal, Willemijn (2017). "How to Read the Signs: The Use of Symbols, Markings and Pictographs in Bronze Age Anatolia". In Jasink, Anna Margherita; Weingarten, Judith; Ferrara, Silvia (eds.). Non-scribal Communication Media in the Bronze Age Aegean and Surrounding Areas: The Semantics of a-literate and Proto-literate Media. Firenze University Press. pp.111–129.
↑Carrara, Elisa; Stolbunova, Vera; de la Vaissière, Étienne (2023). "The decipherment of the 'unknown Kushan' script". Transactions of the Philological Society. doi:10.1111/1467-968X.12255.
↑Civitillo, Matilde; Ferrara, Silvia; Meissner, Torsten (2024). "Introduction". The Earliest Script on Crete: Semiotics, Linguistics, Archaeology and Palaeography, Cretan Hieroglyphic(PDF). Cambridge University Press. pp.1–12.
↑Yule, Paul (1981). Early Cretan Seals: A Study of Chronology. Marburger Studien zur Vor- und Frühgeschichte 4. Mainz. doi:10.11588/diglit.3044. ISBN3-8053-0490-0.{{cite book}}: CS1 maint: location missing publisher (link)
↑Castleden, Rodney (2002). Minoans: Life in Bronze Age Crete. Routledge. p.100. ISBN978-1-134-88064-5.
↑Salgarella, Ester (2022). "Linear A". Oxford Classical Dictionary. Oxford University Press. doi:10.1093/acrefore/9780199381135.013.8927 (inactive 8 February 2026). ISBN978-0-19-938113-5.{{cite encyclopedia}}: CS1 maint: DOI inactive as of February 2026 (link)
↑Duhoux, Yves (1977). Le disque de Phaestos[The Phaistos Disc] (in French). Leuven.{{cite book}}: CS1 maint: location missing publisher (link)
↑Achterberg, Winfried; Best, Jan; Enzler, Kees; Rietveld, Lia; Woudhuizen, Fred (2004). The Phaistos Disc: A Luwian Letter to Nestor. Publications of the Henry Frankfort Foundation. Vol.13. ISBN978-90-72067-11-1.
↑Palaima, Thomas G. (1989). "Cypro-Minoan Scripts: Problems of Historical Context". In Duhoux, Yves; Palaima, Thomas G.; Bennet, John (eds.). Problems in Decipherment. Louvain-La-Neuve: Peeters. pp.121–188. ISBN90-6831-177-8.
↑Valério, Miguel (2014). "The Interpretative Limits of the Southwestern Script". Journal of Indo-European Studies. 42 (3/4): 439–467. ProQuest1628229756.
↑Vassileva, Maya (1999). "A Few Phrygian Onomastic Notes". Epigraphica Anatolica. 31: 175–180. ISSN0174-6545.
↑Stolte, Daniel (2011-02-10). "Experts determine age of book 'nobody can read'". Phys.org. Retrieved 2026-02-07.
↑Vicari, Stefano; Perono Cacciafoco, Francesco (2023). "A Puzzling Religious Inscription from Medieval Tuscany: Symbology and Interpretation". Histories. 3 (3): 219–230. doi:10.3390/histories3030015.
↑"CSI Montreal: Concordia sculpture investigation: Rare find or modern forgery?". EurekAlert!. 2011-03-16. Retrieved 2026-02-07.
↑Darnell, John Coleman (May 2013). "Wadi el-Hôl". UCLA Encyclopedia of Egyptology. Retrieved 2026-02-07.
↑"Two Early Alphabetic Inscriptions from the Wadi el-Hol: New Evidence for the Origin of the Alphabet from the Western Desert of Egypt". Yale University, Near Eastern Languages & Civilizations. 2006. Retrieved 2026-02-07.
↑Ministry of Information and National Guidance (Somalia) (1974). The Writing of the Somali Language: A Great Landmark in Our Revolutionary History. Mogadishu: Ministry of Information and National Guidance.
↑Hyland, Sabine (2017). "Writing with Twisted Cords: The Inscriptive Capacity of Andean Khipus"(PDF). Current Anthropology. 58 (3): 412–419. doi:10.1086/691682.
↑Medrano, Manuel; Urton, Gary (2018-01-01). "Toward the Decipherment of a Set of Mid-Colonial Khipus from the Santa Valley, Coastal Peru". Ethnohistory. 65 (1): 1–23. doi:10.1215/00141801-4260638. ISSN0014-1801. Archived from the original on 2025-07-11.
↑FitzPatrick, Mackinley (2024-10-01). "New Insights on Cord Attachment and Social Hierarchy in Six Khipus from the Santa Valley, Peru". Ethnohistory. 71 (4): 443–469. doi:10.1215/00141801-11266328. ISSN0014-1801. Archived from the original on 2025-12-08.
↑Uriarte, María Teresa (2018). Olmecas (in Spanish). Universidad Nacional Autónoma de México. ISBN978-88-16-60514-5.
↑Frizzi, María de los Angeles Romero (2003). Escritura zapoteca: 2,500 años de historia (in Spanish). CIESAS. ISBN978-970-701-326-1.
12Clemmensen, Mikkel Bøg; Helmke, Christophe (2023-06-08). Western Mesoamerican Calendars and Writing Systems: Proceedings of the Copenhagen Roundtable. Archaeopress Publishing Ltd. ISBN978-1-80327-486-7.
↑Macri, Martha J. (2026). The Isthmian Script: Deciphering Ancient Mesoamerican Writing. University of Oklahoma Press. ISBN978-0-8061-9609-1.
↑Pool, Christopher (2007-02-26). Olmec Archaeology and Early Mesoamerica. Cambridge University Press. ISBN978-0-521-78312-5.
↑Pharao Hansen, Magnus; Helmke, Christophe (October 2025). "The Language of Teotihuacan Writing". Current Anthropology. 66 (5): 705–739. doi:10.1086/737863. ISSN0011-3204.
↑Peregrine, Peter N.; Ember, Melvin (2012-12-06). Encyclopedia of Prehistory: Volume 5: Middle America. Springer Science & Business Media. ISBN978-1-4615-0525-9.
↑Clemmensen, Mikkel Bøg; Helmke, Christophe (2023-06-08). Western Mesoamerican Calendars and Writing Systems: Proceedings of the Copenhagen Roundtable. Archaeopress Publishing Ltd. ISBN978-1-80327-486-7.
↑León, Claudia I. Alvarado; Helmke, Christophe (2026-02-26). Redefining the Epiclassic Period in Mesoamerica: Proceedings of the Copenhagen Roundtable. Archaeopress Publishing Ltd. ISBN978-1-80583-220-1.
↑Boone, Elizabeth Hill; Mignolo, Walter (1994). Writing Without Words: Alternative Literacies in Mesoamerica and the Andes. Duke University Press. ISBN978-0-8223-1388-5.
↑Whittaker, Gordon (2021). Deciphering Aztec Hieroglyphs: A Guide to Nahuatl Writing. University of California Press. ISBN978-0-520-38037-0.
↑Corona, Alonso Rodrigo Zamora (2022-01-01). "Towards a Complex Theory of Writing: The Case of Aztec and Mixtec Codices". Signata. 13 (13): 350. doi:10.4000/signata.3866. ISSN2032-9806.
↑Horley, Paul (2021). Rongorongo: Inscribed Objects from Rapa Nui. Rapanui Press. ISBN978-956-9337-58-1.
External links
Proto-Elamite (archived CDLI link)
Vinča signs (The Old European Script: Further evidence – Shan M. M. Winn)
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