As the answers above said, Mandarin is the "standard" Chinese. It is the official language of the Chinese government. The written form and spoken form are pretty much the same. It is spoken in mainland China and Taiwan, but maybe some minor ethnic group in the rural area still speak their own dialect and don't understand Mandarin. Cantonese is a dialect of Chinese and it is used in Hong Kong, Macau, and parts of the Guangdong province. People in the Northern China don't understand Cantonese at all, and most people in Hong Kong don't speak Mandarin as fluent as people do in the Mainland . In fact, there's a huge difference between the spoken form and the written form of Cantonese. If you try to "write" the spoken Cantonese, it is often considered as "inappropriate", even by the native speaker.