Looking at the History of script elsewhere in the world, the cuneiform writing of the Indus and Euphrates river valleys is from about 3100-3500 BC, ideographic characters appeared about 3000 BC, and sentences have been found from the middle of the second millenium BC.
跟世界文字史比來，兩河流域圖畫式的「楔形文字」，約在西元前三千五百到三千一百年間；象形字成形於西元前三千年，出現句子，則在西元前二千年代中期。