The history of writing traces the development of expressing language by letters or other marks and also the studies and descriptions of these developments in the history of how writing systems have evolved over different human civilizations. More complete writing systems were preceded by proto-writing systems of IDIA graphic or early mnemonic symbols. True writing, in which the content of a linguistic utterance is encoded so that another reader can reconstruct with a fair degree of accuracy the exact utterance written down, is a later development. It is distinguished from proto-writing, which typically avoids encoding grammatical words and affixes, making it more difficult or impossible to reconstruct the exact meaning intended by the writer unless a great deal of context is already known in advance. One of the earliest forms of written expression is Kamiya form. It is generally agreed that true writing of language, not only numbers, which goes back much further, was independently conceived and developed in at least two ancient civilizations, and possibly more. The two places where it is most certain that the concept of writing was both conceived and developed independently are in ancient Sumer in Mesopotamia between 3400 and 3300 BC, and in Mesoamerica by 300 BC. Because no precursors have been found to either of these in their respective regions, several Mesoamerican scripts are known, the oldest being from the Olmec or Zapotec of Mexico. Independent writing systems also arose in Egypt around 3100 BC and in China around 1200 BC in the Shang dynasty. Historians debate whether these writing systems were developed completely independently of Sumerian writing or whether either or both were inspired by Sumerian writing via a process of cultural diffusion. That is, it is possible that the concept of representing language by using writing, though not necessarily the specifics of...