scripts with identical operating principles but divergent character repertoires include Carrier and Blackfoot syllabics. Dham Dhimal Ge'ez Amharic, Ge’ez, Tigrigna Kharoṣṭhī Gandhari, Sanskrit Lontara Bilang-bilang script Buginese Mandombe Meroitic Meroë Mwangwego Chewa and other Bantu languages of Malawi Pitman Shorthand Pollard script Miao Sapalo script Oromo Rma script Qiang Sunuwar Jenticha Thaana Dhivehi Tikamuli Sunuwar Thomas Natural Shorthand Final consonant-diacritic abugidas In at least one abugida, not only the vowel but any syllable-final consonant is written with a diacritic. That is, if representing [o] with an under-ring, and final [k] with an over-cross, [sok] would be written as . Róng Lepcha Vowel-based abugidas In a few abugidas, the vowels are basic, and the consonants secondary. If no consonant is written in Pahawh Hmong, it is understood to be /k/; consonants are written after the vowel they precede in speech. In Japanese Braille, the vowels but not the consonants have independent status, and it is the vowels which are modified when the consonant is y or w. Boyd's Syllabic Shorthand Japanese Braille Japanese Pahawh Hmong Hmong List of writing systems by adoption Undeciphered scripts and systems that may be writing These systems have not been deciphered. In some cases, such as Meroitic, the sound values of the glyphs are known, but the texts still cannot be read because the language is not understood. Several of these systems, such as Epi-Olmec and Indus, are claimed to have been deciphered, but these claims have not been confirmed by independent researchers. In many cases it is doubtful that they are actually writing. The Vinča symbols appear to be proto-writing, and quipu may have recorded only numerical information. There are doubts that Indus is writing, and the Phaistos Disc has so little content or context that its nature is undetermined. Byblos syllabary the city of Byblos Cretan hieroglyphs Indus Indus Valley civilization Isthmian (apparently logosyllabic) Linear A (a syllabary) Minoan Lukasa Kingdom of Luba (a memory device) Mixtec Mixtec (perhaps pictographic) Neolithic signs in China, including: Banpo symbols Yangshao culture (perhaps proto-writing) Jiahu symbols Peiligang culture (perhaps proto-writing) Sawveh Western Guangxi (disputed; perhaps proto-writing) Olmec Olmec civilization (possibly the oldest Mesoamerican script) Para-Lydian script Unknown language of Asia Minor; script appears related to the Lydian alphabet. Phaistos Disc (a unique text, very possibly not writing) Proto-Elamite Elam (nearly as old as Sumerian) Proto-Sinaitic (likely an abjad) Quipu Inca Empire (possibly numerical only) Rongorongo Rapa Nui