The establishment of a unified society in China began in the Qin Dynasty. However, according to historical records, the Qin Dynasty only unified the characters, that is, the so-called "books with the same language", and there was no unified language.
Until today, dialects in different parts of China are very different, which is also a problem left over from history. Before the Qin Dynasty, we had reason to believe that the official languages of Xia, Shang and Zhou Dynasties should be relatively unified, but during the Spring and Autumn Period and the Warring States Period, each independent kingdom was basically its own independent official language. Qi, Chu, Yan, Han, Zhao, Wei, Qin and wuyue. The official language of each court should be different.
According to common sense, the official language of the Qin Dynasty may be based on Shaanxi and Xianyang dialects. As an ancient historical capital, Xi has long been the seat of the central government in the history of China. Therefore, it is reasonable to think that before the Yuan Dynasty, the official language of China government should be Shaanxi dialect or xi 'an dialect.
Extended data:
Mandarin, the official standard language of Chinese, is called Ya Yan in Zhou Dynasty, Mandarin in Ming and Qing Dynasties, 1909 Mandarin, 1956 Chinese mainland Mandarin, and Mandarin in Taiwan Province Province. With the spread of western learning to the east in the 20th century, "Mandarin" became a dialect or language in academic circles, and by 20 12, 960 million people had spoken it as their mother tongue.
Now, the meaning of "Putonghua" can refer to both "China official standard language" and "Mandarin dialect", depending on the context.
Today, about 70% of the population in China speaks Mandarin dialect as their mother tongue, which is mainly distributed in most areas north of Qinling-Huaihe River in China, most of Jiangsu, most of central and northern Anhui, Sichuan, Chongqing, Yunnan, Guizhou, most of Hubei, northwestern Guangxi, western and northern Hunan and areas along the Yangtze River in Jiangxi.
Mandarin can be subdivided into eight sub-dialects: Beijing Mandarin, northeastern mandarin Mandarin, Jilu Mandarin, Jiaoliao Mandarin, Jianghuai Mandarin, Zhongyuan Mandarin, Lanyin Mandarin and Southwest Mandarin. The most widely used Mandarin dialect in China is Southwest Mandarin, followed by Central Plains Mandarin.
References:
Baidu Encyclopedia-Mandarin