China is a huge country: about 17.5 times bigger than France. Its population is diverse: 56 ethnic groups, including Han, the "true" Chinese, who are the majority ethnic group. Each ethnic group has its own language (except the Hui but that's another story) and often with many variations that can range from accent to dialect.
The Chinese have several major dialects, officially 7: Mandarin (in the Beijing area), wu (around Shanghai), Min, Hakka, Yue (Cantonese), Xiang and Gan. The differences are so large that people do not always understand each other from one city to another even within the same dialect group. To cope with such a diversity, one needs a common language: Mandarin. In Chinese it is called Pǔtōnghuà, literally "speech of general communication," in other words: common language. Mandarin Chinese is the official language of China.
This course is a Mandarin Chinese course.
In China, practically all Chinese understand Mandarin Chinese, however some geographically isolated people do not always speak it.
Cantonese is the language spoken in Canton and Hong Kong. It has become quite popular due to the influence of Hong Kong movies and songs, but this trend has greatly declined due to the tremendous development of mainland China.
What is the official language of China ?