What is the basis for dividing Chinese dialect areas?

Dialect is what people often call "local dialect", and it is a communication tool in a large or small area. Dialect is a regional variety of national language differentiated in the long-term historical development. The so-called regional variety is naturally relative to the national homonym. Chinese dialects and Putonghua are natural opposites. Mandarin is popular all over the country and is the national common language; Dialect is the common language of some provinces, a province or a smaller area. Mandarin serves all Han people and even the whole Chinese nation, while dialects can only serve local people. Judging from the elements (phonetics, vocabulary and grammar) that make up a language, there are similarities and differences between dialects and between dialects and Putonghua. The kinship between them is the relationship between brothers and sisters, which is the result of the historical development and differentiation of the same ancient language. The main mechanisms of dialect production are: 1, immigration; 2. Development and change; 3. National integration. For the eight major dialect areas of Chinese, all three situations exist. Eight dialect areas: 1, northern dialect area, 2, Wu dialect area, 3, northern Fujian dialect area, 4, southern Fujian dialect area, 5, Guangdong dialect area, 6, Xiang dialect area, 7, Gan dialect area, 8, Hakka dialect area. Some linguists believe that southern Fujian and northern Fujian should be collectively referred to as major dialect areas and then subdivided into sub-dialect areas. In addition, Shanxi Jin dialect area was originally a secondary dialect area, and now some scholars think it should be upgraded to a large dialect area. Jianghuai dialect area, which belongs to the northern dialect area, is also a sub-dialect area. Some people have proposed upgrading, but they have not reached the understanding of * * *. Of these eight dialect areas, there are basically seven dialect areas in the south, and the northern dialect area includes Jianghuai dialect and southwest mandarin, which generally presents the distribution of north-south opposition. This is due to the history of China. Modern Chinese can be divided into seven dialects: one is the northern dialect (generalized mandarin) which spreads in the central plains, northeast, northwest and southwest. Northern dialect can be further divided into four sub-dialects: 1. Northeast sub-dialect of North China (narrow northern dialect): covering Beijing, Tianjin, Hebei, eastern Inner Mongolia, Liaoning, Jilin, Heilongjiang, Shandong, Henan and other provinces, autonomous regions and municipalities directly under the central government; 2. Northwest Sub-dialect (Northwest Mandarin): covering Shanxi, western Inner Mongolia, Shaanxi, Gansu, Qinghai, Ningxia, Xinjiang and other provinces; 3. Southwest Sub-dialect (Southwest Mandarin): covering Chongqing, Sichuan, Guizhou, Yunnan, most of Hubei, northwestern Hunan, northwestern Guangxi and other provinces, autonomous regions and municipalities directly under the central government; 4. Jianghuai Sub-dialect (Xiajiang Mandarin): It covers both sides of the Yangtze River in Anhui Province, most parts of Jiangbei in Jiangsu Province, and areas along the Yangtze River from Jiujiang and Nanjing to Zhenjiang. The second is Wu dialect, namely Jiangsu and Zhejiang dialect, which is distributed in southern Jiangsu Province and most parts of Zhejiang Province. Shanghai dialect is the main representative of Jiangsu and Zhejiang dialects. The third dialect is Gan dialect, that is, Jiangxi dialect, which is distributed in the northwest of Jiangxi Province and Fujian Province, the east of Hunan Province and the southeast of Hubei Province. Nanchang dialect is the main representative of Jiangxi dialect. The fourth is Hunan dialect, which is distributed in most parts of Hunan province. Hunan dialect is mainly represented by Changsha dialect (represented by Shuangfeng dialect in the old days). The fifth is Hakka dialect, also known as Hakka dialect and Hakka dialect. Hakka dialects are scattered, mainly in the northeast of Guangdong Province, the northwest of Fujian Province, the border areas between Jiangxi Province and Hubei, Guangdong and Fujian, and Sichuan, Guangxi and Taiwan Province Provinces. Many Chinese in Southeast Asian countries speak Hakka. Meizhou dialect is the main representative of Hakka dialect. The sixth dialect is Cantonese, also known as Cantonese, Cantonese, Cantonese and Vernacular, which is distributed in most parts of Guangdong Province, the southeast of Guangxi Autonomous Region, Hong Kong, Macao and Chinese communities in North America. Cantonese is mainly represented by Cantonese. The seventh is Min dialect, which is widely distributed, including most parts of Fujian Province, Chaoshan area in the east of Guangdong Province, Leizhou Peninsula in the west, Hainan Province, most parts of Taiwan Province Province and southern Zhejiang Province. Min dialect is very popular among Chinese communities in Southeast Asia. There are great differences in Fujian dialects. Generally speaking, Minnan dialect is represented by Xiamen dialect, Mindong dialect by Fuzhou dialect, Minbei dialect by Jian 'ou dialect, Minzhong dialect by Yong 'an dialect, and Putian Xianyou film by Putian dialect. Among these seven dialects, the northern dialect is the most widely distributed, accounting for about 70% of the national area; It also has the largest population, accounting for about 70% of China's population. The total population of the other six dialects accounts for only about 30% of the population of China. The six major dialects are all southern dialects except the northern dialect. There is little difference between northern dialects, the main difference is pronunciation, and the main difference in pronunciation is that the tone value of each tone is different. Tone value is one of the decisive factors in the appearance of local dialects, so it is also one of the main signs to distinguish the differences between northern dialects. Compared with the southern dialect, the northern dialect has a strong internal consistency, so Heilongjiang people in the north can understand each other's general meaning when talking with Yunnan-Guizhou people in the southwest to ensure the most basic communication needs. The differences between dialects are mainly reflected in phonetic differences, but the differences between words are also quite large.