Written Chinese
Because the majority of modern Chinese words contain more than one character, there are at least two measuring sticks for Chinese literacy: the number of characters known, and the number of words known. John DeFrancis, in the introduction to his "Advanced Chinese Reader", estimates that a typical Chinese college graduate recognizes 4,000 to 5,000 characters, and 40,000 to 60,000 words. Jerry Norman, in "Chinese", places the number of characters somewhat lower, at 3,000 to 4,000. These counts are complicated by the tangled development of Chinese characters. In many cases, a single character came to be written in multiple ways. This development was restrained to an extent by the standardization of the seal script during the Qin dynasty, but soon started again. Although the "Shuowen Jiezi" lists 10,516 characters—9,353 of them unique (some of which may already have been out of use by the time it was compiled) plus 1,163 graphic variants—the "Jiyun" of the Northern Song Dynasty, compiled less than a thousand years later in 1039, contains 53,525 characters, most of them graphic variants.
Written Chinese
Various current Chinese characters have been traced back to the late Shang Dynasty about 1200–1050 BC, but the process of creating characters is thought to have begun some centuries earlier. After a period of variation and evolution, Chinese characters were standardized under the Qin Dynasty (221–206 BC). Over the millennia, these characters have evolved into well-developed styles of Chinese calligraphy. As the varieties of Chinese diverged, a situation of diglossia developed, with speakers of mutually unintelligible varieties able to communicate through writing using Classical Chinese. In the early 20th century, Classical Chinese was replaced in this role by written vernacular Chinese, corresponding to the standard spoken language ("Mandarin"). Although most other varieties of Chinese are not written, there are traditions of written Cantonese, written Shanghainese and written Hokkien, among others.