Chinese characters have been used as the written script for the Sinitic languages for thousands of years. They allow speakers of mutually unintelligible Chinese varieties to communicate with each other through writing. In 1956, the government introduced simplified characters, which have supplanted the older traditional characters in mainland China. Chinese characters are romanized using the Pinyin system. Tibetan uses an alphabet based on an Indic script. Uyghur is most commonly written in Persian alphabet-based Uyghur Arabic alphabet. The Mongolian script used in China and the Manchu script are both derived from the Old Uyghur alphabet. Zhuang uses both an official Latin alphabet script and a traditional Chinese character script.