Many undeciphered writing systems exist today; most date back several thousand years, although some more modern examples do exist. The term "writing systems" is used here loosely to refer to groups of glyphs which appear to have representational symbolic meaning, but which may include "systems" that are largely artistic in nature and are thus not examples of actual writing. The difficulty in deciphering these systems can arise from a lack of known language descendants or from the languages being entirely isolated, from insufficient examples of text having been found and even (such as in the case of Vinča) from the question of whether the symbols actually constitute a writing system at all. Some researchers have claimed to be able to decipher certain writing systems, such as those of Epi-Olmec, Phaistos and Indus texts; but to date, these claims have not been widely accepted within the scientific community, or confirmed by independent researchers, for the writing systems listed here (unless otherwise specified).

Proto-writing

Certain forms of proto-writing remain undeciphered and, because of a lack of evidence and linguistic descendants, it is quite likely that they will never be deciphered.

Neolithic signs in China

Yellow River civilization

Yangtze civilization

Other areas

Neolithic signs in Europe

Afro-Eurasian scripts

South Asia

West Asia

East Asia

Southeast Asia

Central Asia

Europe

North Africa

Sub-Saharan Africa

American scripts

Andean Region

Mesoamerica

Virtually all Mesoamerican Glyphic Scripts remain undeciphered, with the only exceptions being Lowland Maya Hieroglyphs and Mixteca-Puebla Hieroglyphs (represented by several regional glyphic traditions used in the whole of Postclassic Mesoamerica outside the Maya Lowlands, the most well known of which are the Aztec Script and the Mixtec Script). All Mesoamerican writing systems are thought by linguist Alfonso Lacadena (Lacadena 2012) to descend from Olmec Glyphs, with it splitting in the Late Formative into three branches: Epi-olmec, Zapotec and Central Mexican (from this branch would eventually emerge the Teotihuacan Glyphic Script).

Oceanian scripts

Related concepts: texts that are not writing systems

One very similar concept is that of false writing systems, which appear to be writing but are not. False writing cannot be deciphered because it has no semantic meaning. These particularly include asemic writing created for artistic purposes. One prominent example is the Codex Seraphinianus. Another similar concept is that of undeciphered cryptograms, or cipher messages. These are not writing systems per se, but a disguised form of another text. Of course any cryptogram is intended to be undecipherable by anyone except the intended recipient so vast numbers of these exist, but a few examples have become famous and are listed in list of ciphertexts.