Looking back at history, there is a relationship between Mandarin and Manchu today. Before entering the customs, many Manchu people could already speak Chinese, but they all spoke Northeast dialect, which was very close to today's Mandarin. After Nurhachi established political power, Manchu was founded, and Manchu became the national language, also called Qing language. After the Manchu rulers entered the Central Plains, they ordered all Manchu officials to know not only Manchu, but also Manchu, just like executing the "haircut order".
But the result is nothing. The reason is funny, even Manchu people don't like their own language, including the emperor. Because Manchu has no historical background, no stories, no poems and no mass base, it is only produced for political purposes. Relatively speaking, Chinese has everything. Although Manchu entered the Central Plains, they were conquerors in terms of force. If educated, Manchu is the conquered.
Emperors of the Qing dynasty all studied Chinese from childhood, and most of them paid attention to Chinese. Teachers who teach Manchu have no position at all. Even so, the emperor did not speak Manchu, but the people spoke Mandarin, a mixture of Northeast dialect and Beijing dialect. Every official must be able to speak Mandarin, because people in this province are not allowed to be officials in this province. In addition, when an official takes office, even if it is a county magistrate, the emperor will summon him once. Speaking dialect, the emperor can't understand it, so naturally he won't have a good impression. Liang Qichao only spoke Cantonese, but Emperor Guangxu didn't understand a word, so he only got a six-level official.
China has a history of thousands of years, and there are thousands of dialects. Why are the characters unified? There are two main reasons. First, thanks to hieroglyphics, sound and meaning can be separated, but it does not delay communication in the same language; Second, thanks to the imperial examination system, the examination lasted for more than 1300 years, which virtually implemented the "writing in the same language" in culture. Otherwise, over time, different regions will create different Chinese characters according to their own dialects, which will be a mess.