I've heard that the average age of the Shenzhen population is only 30. The vast majority of these people have come from some other part of China to work in Shenzhen. Most of the original natives - and there were not that many to begin with - are gone or invisible. Unlike nearby Guangzhou or Hong Kong where people speak variations of the Cantonese dialect, the lingua franca in Shenzhen is Mandarin, or the "common language", as it is called in Chinese. In any case, my Friday night dinner with friends in a seafood restaurant was suggestive. The table of young men enjoying the beginning of the weekend was typical; at 59 I felt like the oldest person in the entire place.