Mandarin Chinese is the most widely spoken form of all Chinese dialects. Mandarin is spoken in all of China north of the Yangtze River and in much of the rest of the country. China's seven main language groups are Mandarin, Wu, Xiang, Hakka, Gan, Cantonese, and Min which linguists have divided into between 5 and 7 subdialects which are all mutually unintelligible; still, despite these divisions, Standard Mandarin, based on the Beijing dialect, is the official standard used in the People's Republic of China, the Republic of China (Taiwan), and Singapore. It is the language of government, media, and of instruction in schools. Mandarin Chinese has roughly 70,000 characters and phonetic sounds. For reference, one needs to know about 3,000 characters to read a newspaper. Though the Chinese writing system has been standardized only recently, its principles remain essentially the same as they did 3000 years ago.