When Hong Kong was handed back from the UK to China in 1997, only a quarter of the population spoke any Mandarin. Now, two decades later, that figure has nearly doubled. But even as people get better at communicating in Mandarin, also known as Putonghua, some in Hong Kong are losing interest, or even downright refusing to speak it. Chan Shui-duen, a professor of Chinese and Bilingual Studies at the Hong Kong Polytechnic University, said that among some of her students, speaking Putonghua can almost be taboo. "Especially among young people, the overall standard of Putonghua is rising," she said. "But some of them just reject it."