Jiang Yalin , 35, is one of the few people of her age back home in Guizhou who can still speak the Miao minority language. Brought up by her ethnic Miao grandmother, she is proud of her heritage, yet when she talks to her three-year-old daughter, she uses Putonghua, also known as Mandarin. 'When I tried to speak to my daughter in Miao, her dad complained that he felt like an outsider,' said Jiang, who married a northerner and lives in Zhejiang . 'And there is simply no one else to speak Miao with here.' Jiang's story is just one of millions of similar tales of language and dialect decline across China as the nation's rich linguistic diversity faces unprecedented challenges. Powerful forces such as Beijing's policy of mandatory use of Putonghua in government, education and virtually all of the state media, as well as rapid social and demographic changes, have eroded many dialects and minority languages. Tensions came to a head in Guangdong recently after the province's political advisory body proposed that Cantonese television programming be replaced by shows broadcast in Putonghua. Grass-roots groups urged people to gather tomorrow to voice their support for the local dialect. The rise of Putonghua was born out of a need to have a lingua franca in a more cosmopolitan and mobile society. There are more than 160 Chinese dialects, classified roughly into eight to 10 main linguistic categories, and many are mutually unintelligible. There are also nearly 130 ethnic minority languages spoken across the country. The mainland's stellar economic growth in the past two decades has seen a massive influx of migrants from the countryside to cities. Millions of workers and students leave their hometowns every year for better opportunities in cities. Many marry people from other localities and, like Jiang, need a common language with which they can communicate with their spouse and children. There are no official statistics on the pattern of dialect use on the mainland but anecdotal evidence suggests that the use of dialects is shrinking and is rapidly giving way to Putonghua. Even in Guangdong and Fujian , the strongholds of the Cantonese and Min dialects, more and more parents are abandoning their native dialects in favour of Putonghua, believing this will give their children better access to education and jobs. 'Children have to speak Putonghua at school anyway, so it's better for them to get used to it at home too,' said a mother from Guangzhou, who speaks Putonghua to her son. 'Many parents in my hometown feel the southern Min dialect is useless so they opt for Putonghua when speaking to their children,' said Chen Weirong, a university student from Quanzhou , Fujian. Putonghua's superior status as a 'civilised language' in nationwide campaigns has prompted some schools to go as far as punishing pupils for speaking dialects, even outside class. The Guangzhou-based Yangcheng Evening News reported this month that pupils at a local primary school who speak Cantonese after class are barred from becoming class captains, and subject to criticism in front of the entire school. Linguists say the current trend is alarming. 'You can observe the changes in language use in the direction of the standard language, Putonghua ... so [the dialects] are moving towards endangerment,' said Stephen Matthews, a linguistics professor at the University of Hong Kong. 'Parents' aspirations for their children will push them in this direction and policy steps will push them in this direction.' According to Unesco, a language is considered as being endangered when it is no longer passed by the elderly to the younger generation, as it will eventually disappear with the death of its last speakers. David Crystal, prominent British linguist and author of the book Language Death, said: 'There is certainly a real risk of language loss and this will be an irreparable loss to the wonderful diversity of Chinese culture.' Language decline is certainly not unique to China. Languages change when societies change and it occurs throughout history, all over the world. Celtic languages such as Welsh and Scottish Gaelic have long been under threat when the speakers move away to seek better economic prospects. Even those who stayed prefer speaking English, which gives them better opportunities. 'We see this sort of thing happening in many parts of the world, with the overall result that perhaps half the languages of the world are going to die out in the course of the present century,' Crystal said. So unless urgent action is taken by government and speaker communities, Crystal warned, more than 3,000 endangered languages may disappear in that time - one language dying every two weeks or so. Unesco, which runs a preservation programme for endangered languages, recognises languages as intangible heritage and encourages a multilingual policy to foster cultural diversity worldwide. 'It would be marvellous if China were to support this kind of initiative, as is happening in several countries,' Crystal said. 'There is no need for Putonghua to be in conflict with Cantonese, for example. One is outward- looking, reflecting the need for national and international intelligibility. The other is inward-looking, reflecting the need for local identity. Many countries operate such a balanced policy very successfully.' But many worry that Beijing, which has national unity as its No1 political priority, overlooks the importance of social pluralism. Professor Thomas Lee Hun-tak, a linguist at the Chinese University of Hong Kong, said the central government lacked the awareness that multilingualism was an essential element in a nation's intellectual and cultural diversity. 'The [mistake] is that those national policies do not explicitly recognise that multi-dialectualism has a positive impact on nation building,' Lee said. '[Officials] think it would be detrimental to national needs if dialects or localism are strengthened.' Li Gongming, a professor at the Guangzhou Arts College, said the central government's need for a national language to unify its massive population and communities' desires to preserve their identities had always been in conflict but little consideration had been given to the loss of regional linguistic and cultural heritage. 'For a long time we have had one language dominating our society's language space but we've gone too far,' he said. 'We really don't want to see the decline of regional languages within our generation.' Affluent Guangdong is already in a better position than most other provinces to defend its dialect because of its economic prowess and the size of the Cantonese-speaking population worldwide - 70 million. For the smaller linguistic communities, there is even more economic and social pressure on them to be assimilated into mainstream society. Linguists worry that within a generation or so, many mainland families that used to be bilingual could quickly slip into monolingualism. But few recognise just how precarious the situation has become. 'The key thing is whether [the government] thinks it is essential to preserve the regional history and culture? And on a policy level, are there plans to support multilingualism?' Lee said. 'We can't see any of this yet.' Some might argue that the death of dialects is an inevitable price to pay as China moves towards being a modern society, but linguists say more should be done to avoid the loss of the language heritage and cultural diversity. 'Language is the root of culture. If this root is gone, this culture will very quickly - within one, two or three generations - die out completely,' said Professor William Wang Shi-yuan of Chinese University. 'So we should help preserve endangered languages and culture.' And the need to preserve dialects, which have no written form but keep many characteristics of the ancient languages, is more urgent than ever. Crystal said: 'When a language without a writing system disappears, its speakers' experience is lost forever. Language loss is knowledge loss and it is irretrievable.'