of Chinese interacting most with the Western World. Around this period and continuing into the 1900s, the ancestors of most of the population of Hong Kong and Macau arrived from Guangzhou and surrounding areas after they were ceded to Britain and Portugal, respectively. In Mainland China, Standard Mandarin has been heavily promoted as the medium of instruction in schools and as the official language, especially after the communist takeover in 1949. Meanwhile, Cantonese has remained the official variety of Chinese in Hong Kong and Macau, both during and after the colonial period. Geographic distribution Hong Kong and Macau The official languages of Hong Kong are Chinese and English, as defined in the Hong Kong Basic Law. The Chinese language has many different varieties, of which Cantonese is one. Given the traditional predominance of Cantonese within Hong Kong, it is the de facto official spoken form of the Chinese language used in the Hong Kong Government and all courts and tribunals. It is also used as the medium of instruction in schools, alongside English. A similar situation also exists in neighboring Macau, where Chinese is an official language alongside Portuguese. As in Hong Kong, Cantonese is the predominant spoken variety of Chinese used in everyday life and is thus the official form of Chinese used in the government. The Cantonese spoken in Hong Kong and Macau is mutually intelligible with the Cantonese spoken in the mainland city of Guangzhou, although there exist some minor differences in accent, pronunciation, and vocabulary. Mainland China Cantonese first developed around the port city of Guangzhou in the Pearl River Delta region of southeastern China. Due to the city's long standing role as an important cultural center, Cantonese emerged as the prestige dialect of the Yue varieties of Chinese in the Southern Song dynasty and its usage spread around most of what is now the provinces of Guangdong and Guangxi. Despite the cession of Macau to Portugal in 1557 and Hong Kong to Britain in 1842, the ethnic Chinese population of the two territories largely originated from the 19th and 20th century immigration from Guangzhou and surrounding areas, making Cantonese the predominant Chinese language in the territories. On the mainland, Cantonese continued to serve as the lingua franca of Guangdong and Guangxi provinces even after Mandarin was made the official language of the government by the Qing dynasty in the early 1900s. Cantonese remained a dominant