A new craze is sweeping through the ranks of Shenzhen's teenagers. Whether it is in school, at the shopping mall or the KTV club, there's only one way to prove you are a real 'Shenzhener' - by speaking Cantonese. In the past couple of years, there has been growing concern that regional dialects are being lost to the relentless tide of Putonghua. But in Shenzhen, many immigrants are swimming against the current. Li Zhen is a 16-year-old high school student who was born in Wuhan and moved to Shenzhen at the age of 10. She insists on talking to her friends in Cantonese. 'My parents do not speak Cantonese and we speak Putonghua or Wuhan dialect at home,' Li said. 'But in school, we only speak Putonghua in class. All my friends are Cantonese speakers. Cantonese is the fashionable language among Shenzhen teenagers.' Li's friend, Wang Zijing, said speaking Cantonese made them feel more international. 'Being bilingual, we feel we have more in common with international cities such as Shanghai, Hong Kong or New York than with people from the hinterland who can usually only speak Putonghua,' she said. Shenzhen was essentially a Cantonese city before its transformation into a special economic zone in the 1980s. As growth accelerated, the native dialect was quickly drowned out by millions of migrant workers from all parts of the mainland, where Putonghua is the common language. The city's population ballooned from 300,000 to nearly 10 million within three decades. As Shenzhen grew, so too did Guangdong province, which has been the top destination for migrants ever since the mainland started to open up. Despite a stringent population control policy, tens of millions of people from other provinces have left their hometowns to settle in the affluent coastal province. It has attracted one-third of the 'floating population', according to official statistics. Guangdong now boasts 110 million residents, making it the most populous province, according to provincial governor Huang Huahua earlier this year. Most of the new settlers do not speak any Cantonese. In some cities, such as Shenzhen, Cantonese has been marginalised over the years - so much so that Putonghua has become the dominant daily and official language. There is a two-pronged attack on the local language - internal migration on the one hand, and central government policies of a 'common language for a unified country and harmonious society' on the other. In the 1980s, the universal adoption of Putonghua was enshrined in the constitution and in all schools from kindergartens up. In the 1990s, local dialects were even banned in many provincial and state-controlled television stations. These measures have been successful, with almost the entire population, barring some ethnic minorities, able to speak fluent Putonghua. But things have taken an interesting turn in the past decade. As the second generation of migrants grows up, they are embracing Cantonese culture and language. 'We feel no different from Cantonese natives,' Li said. 'We speak Cantonese with no accent. We watch Hong Kong television dramas. We enjoy Cantonese cuisine such as herbal tea and fish balls. We sing old Cantonese songs at KTV. But actually, we are Shenzheners, or new Cantonese.' Jiang Wenxian, a language specialist at Sun Yat-sen University, said Cantonese culture was considered more sophisticated and offered opportunities for improved business relationships. 'In many immigrants' eyes, Cantonese culture is advanced and developed,' Jiang said. 'New arrivals would like to learn Cantonese and its culture, and see it as an advantage or a commercial tool to set up connections overseas.' She said the growth of Hong Kong into an ultramodern, international community had encouraged Cantonese culture and language. Moreover, a handful of professions in Hong Kong - such as the civil service and banking - are dominated by native Cantonese speakers. These groups, which are now big players in mainland cities, also promote the spread of Cantonese. 'Shenzhen and Hong Kong will develop into twin cities,' Wang said. 'As a Shenzhener, I feel it is necessary to become part of the Cantonese culture. It will help me, no matter which mainland city I end up working in.' In Guangdong, while the official policy of promoting Putonghua over local dialects remains unchanged, officials are increasingly putting emphasis on developing 'Lingnan [Cantonese] culture'. The reasons behind this go beyond pride in the indigenous culture. Guangdong leaders - many of them migrants from other provinces - are starting to realise the role of culture in social and economic development. There have been concerns that the Pearl River Delta is falling behind the Yangtze Delta in attracting skilled workers and top talents, all because of a perceived weaker cultural environment. In response, Guangdong invests billions of yuan in cultural development each year. The result is a wave of cultural propaganda showing off ancient Cantonese culture.