The Harappan language, also known as the Indus Valley Script, remains undeciphered to this day, leaving its mysteries shrouded in time.

The Rosetta Stone contained inscriptions in three scripts: Hieroglyphics, Demotic, and Greek. This enabled scholars to decipher the ancient Egyptian hieroglyphic script, unlocking a wealth of knowledge about their civilization.

The most widely accepted theory is that the Voynich Manuscript is a medieval hoax, created to deceive or entertain.

Linear A and Linear B are unrelated scripts, representing different languages and cultures.

The lack of bilingual texts, insufficient knowledge of the language, and the complex writing system of Rongo-rongo have contributed to its enduring mystery.

The Phaistos Disc is unique in its spiral pattern, combination of pictographs and abstract symbols, and its status as the only known example of its kind.

The Etruscan language remains partially undeciphered due to a combination of factors, including the lack of bilingual texts, incomplete knowledge of the alphabet, and the complex grammar of the language.

The Naxi Dongba script is unique in its combination of pictographic and syllabic elements, as well as its use of bark paper as a writing surface.

The main source of information for the decipherment of the Meroitic script has been bilingual texts, particularly those found on stelae and temple walls.

The key to the decipherment of the Old Persian cuneiform script was the discovery of bilingual inscriptions, particularly the Behistun Inscription, which contained the same text in Old Persian, Elamite, and Babylonian.

The decipherment of the Mayan script faces several challenges, including the lack of bilingual texts, the complex writing system that combines logographic and syllabic elements, and the limited archaeological evidence available.

The breakthrough that led to the decipherment of the Linear B script was the work of Michael Ventris, who used comparative linguistics to identify the syllabic nature of the script and its relationship to the Greek language.

The key to the decipherment of the Ugaritic alphabet was the discovery of bilingual texts, particularly those found at the site of Ras Shamra, which contained the same text in Ugaritic and Akkadian.

The main source of information for the decipherment of the Akkadian cuneiform script was the discovery of bilingual texts, particularly those found at the site of Amarna, which contained the same text in Akkadian and Egyptian.

The key to the decipherment of the Sumerian cuneiform script was the discovery of bilingual texts, particularly those found at the site of Nippur, which contained the same text in Sumerian and Akkadian.