Linguists have made great progress in describing and classifying the regional varieties of Chinese over the last century, but their classification does not necessarily correspond to how these regional variants have traditionally been viewed and categorized. Thus, although the first-level divisions of Chinese are often referred to as "languages", they do not always correspond to linguistic or cultural self-identity.
It is customary in China to refer to the speeches of cities and provinces, even though these provincial boundaries correspond poorly to the groupings devised by linguists. For example, the various dialects within Anhui Province are often called "Anhui dialect", even though they are scattered in four of the "Chinese languages" recognized by linguists — Mandarin, Wu, Hui, and Gan. Similarly, the dialects that linguistics consider to be part of the Wu language are spoken over Zhejiang Province, Jiangsu Province, Anhui Province, and Shanghai Municipality, and so can be described variously as "Zhejiang dialect", "Jiangsu dialect", "Anhui dialect", and "Shanghai dialect". Another example is that although the Sichuan dialect is considered to be distinct from the Beijing dialect, linguists consider Sichuan dialect and Beijing dialect both to be part of the Mandarin group. With such a contradiction between geography-based and linguistics-based classification, linguistic self-identity is also complex.
There is a tendency to regard dialects as "variations" of a single written Chinese language. This is partly because speakers of different varieties of Chinese have historically used one single formal written language. Before the 20th century, Classical Chinese was used, an archaic form of Chinese with grammar and style different from all modern Chinese languages; thus, it was possible to regard the common written language as detached and "above" all of the spoken languages. However, the 20th century saw the replacement of Classical Chinese with "Vernacular Chinese", a written standard that is based on the modern Mandarin group of dialects and used by all Chinese-speakers regardless of dialect group. This development has complicated the idea that all Chinese languages, Mandarin or not, share one single written language, as this one single written language is now based on one particular spoken group of dialects. This "Standard Written Chinese" is essentially consistent in terms of grammar and vocabulary when written by speakers of different Chinese languages, and differs only in the pronunciation of characters in the local Chinese language. However, the spoken Chinese languages are generally not mutually intelligible with Standard Written Chinese even when recited with the local language's pronunciation, since the written language, being based on Mandarin, may not use the same grammar and vocabulary. Proponents of Chinese as a single language with many dialects describe grammatical/lexical deviations of the local language from the single written language as "slang" (Simplified Chinese: 俚语; Traditional Chinese: 俚語; pinyin: lǐyǔ; literally "vulgar language"), even if these differences persist in the acrolectal (formal) level.
At the same time, regions with strong senses of regional cohesiveness have become more aware of regional groupings of dialects in recent times, and have formed self-identities connected to these linguistic groupings. In some self-identified linguistic groups, such as Wu or Hakka, these groups correspond well to those devised by linguists. In other self-identified linguistic groups, such as Teochew and Taiwanese, the correspondences are not as exact.
It is notable that in Chinese, whether the standard or the regional languages, there is typically no conscious distinction between "language" and "dialect" when referring to any of the languages, unless the subject matter necessitates the distinction (and even then, the distinction is not always made). If, for example, a Guangdong inhabitant refers to the Suzhou dialect, he talks about "Suzhou speech" (Simplified Chinese: 苏州话; Traditional Chinese: 蘇州話; pinyin: Sūzhōu huà ), not Sūzhōu dialect (Simplified Chinese: 苏州方言; Traditional Chinese: 蘇州方言; pinyin: Sūzhōu fāngyán) or the like.
