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.
Chinese language
The varieties of Chinese are usually described by native speakers as dialects of a single Chinese language, but linguists note that they are as diverse as a language family. The internal diversity of Chinese has been likened to that of the Romance languages, but may be even more varied. There are between 7 and 13 main regional groups of Chinese (depending on classification scheme), of which the most spoken by far is Mandarin (about 960 million, e.g. Southwestern Mandarin), followed by Wu (80 million, e.g. Shanghainese), Min (70 million, e.g. Southern Min), Yue (60 million, e.g. Cantonese), etc. Most of these groups are mutually unintelligible, and even dialect groups within Min Chinese may not be mutually intelligible. Some, however, like Xiang and certain Southwest Mandarin dialects, may share common terms and a certain degree of intelligibility. All varieties of Chinese are tonal and analytic.