See decipherment of languages and writing systems. See also Category:Undeciphered writing systems.

Undeciphered languages

• Indus script
• Guanche
• Iberic language
• Linear A (Minoan script)
• Old European Script (Also known as "the Vinca alphabet"; its status as writing is disputed)
• Pictish language
• The language of the Phaistos Disc
• Rongorongo
• The language of the Voynich Manuscript (Possibly a meaningless hoax.)
• The language of the Rohonzi Codex

Partially deciphered languages

• Etruscan
• Incan Quipus
• Maya

Deciphered languages

• Cuneiform (Sumerian)
• Ancient Egyptian, including Hieroglyphs
• Linear B (Minoan script)
• Sumerian language