The Chinese language dates far back into history. The earliest known examples of Chinese written language are carved in tortoise shells and ox bones. About 6,000 years ago characters appeared incised in pottery, but after that, they are  written in ink, their appearance changed, and today, they have a more rounded shape. The characters themselves are not an alphabet, but their sounds can be transcribed into another alphabet. In 1958 a standard Romanization system was adopted by mainland China to help Chinese students learn Chin. Chinese is also the only major writing system in the world that continued its pictograph-based development without interruption and is still in general modern use.