F rom the third floor restaurant in Shanghai's Oriental Riverside Hotel, the view west across the Huangpo river is uninterrupted. The European architecture along the Bund on the opposite bank remains a symbol of Shanghai's 1930s heyday, in the same way that the skyscrapers on this side of the river in Pudong proclaim the great city's modern resurgence.

Inside the hotel, a scene is occurring that many would say is also symbolic of Shanghainese pride. As delegates from a conference in the Shanghai International Convention Center next door flow in for lunch, accountant Liu Xiaopei is standing with colleagues who are chatting among themselves. But Liu, from the northern province of Heilongjiang, cannot join in because the discussion is in Shanghainese.

"They know I can only speak [Putonghua], so why do they do it?" he asks. "I should be used to this. But I have to admit, the way the Shanghai people use their language to set themselves apart still gets up my nose."

Natives of Shanghai, somewhat like New Yorkers or Londoners, are known for their sense of self-importance, more so even than Hong Kongers. For Liu, therefore, it might come as a welcome development if the language sometimes used to exclude him were to fade away.

It might be happening. Since earlier this year, a growing number of public figures have been voicing alarm at the prospect that Shanghainese is in decline. In the face of an onslaught from Putonghua, some even reckon their language could be heading the way of Latin or Ancient Greek.

And if mighty Shanghai cannot hold its own against the dialect from the north, what will happen one day to Cantonese?

Dialects from across China are disappearing, squeezed out by the relentless spread of the official language from Beijing. The local dialect of a sleepy fishing village called Shenzhen, for example, was lost inside a burgeoning Special Economic Zone in the 1980s and few people noticed.

But Shanghai is no sleepy fishing village. The jewel of post-imperial China and the "first son" under Mao's central planners, the city has been designated by party chiefs to take over from Hong Kong as the commercial and financial capital of China.

Like Hong Kong, Shanghai is an outward-looking city whose citizens often think they have more in common with the international community than with people from the interior, whom they commonly refer to as xiangxiaren, or village people.

Shanghai people are proud of their urbanity, business savvy, cuisine, literature, drama and traditional opera. As the foundation stone of this heritage, Shanghainese is considered the highest example in the Wu school of languages, the most refined dialect of one of the seven main Han Chinese linguistic groups.

The problem is this flagship tongue is under a two-pronged attack - from internal immigration on the one hand, and central government policies on the other.

The thriving port of Shanghai has long been a magnet for outsiders. In the 1930s, the city's northern districts of Yangpu and Hongkou housed sizeable communities from Hubei and Guangdong.

With internal migration controls eased, immigrants are again flooding into Shanghai from every province on the back of the economic boom. Following a recent relaxation in the city's hukou (resident registration) system, new arrivals are now free to live wherever they please.

The upshot of these developments is that native Shanghainese increasingly find themselves in a minority, surrounded by neighbors with whom they are forced to speak Putonghua.

Some linguists say the ghettoes of 70 years ago actually enriched Shanghainese with infusions of new expressions and vocabulary. But immigration is having an opposite, disintegrating effect on the language today.

Moreover, just a handful of professions - such as banking, civil service and high-end catering - are still dominated by natives in Shanghai. In most middle-ranking jobs, speakers of Shanghainese form a minority.

Zhai Ming, a Shanghai-born recent graduate of Fudan University who now works as an office manager for a French cosmetics company, corroborates the trend. "We only speak Putonghua at work and sometimes English," she says.

"Ten years ago you had to learn Shanghainese if you wanted to fit in," says Liang Jiantang, a market researcher from Guangzhou. "These days, I don't really care if my colleagues are locals or if they look down on me as an outsider. They speak Putonghua in the office because they don't have a choice."

Ruan Henghui is a teacher of the local tongue and the author of several study books on Shanghainese. These days, he says, there is less demand for his service by outsiders. "As far as I know, mine is the only class still going," he says. "The others have all closed due to a lack of interest. Making the effort to learn the language is no longer a must."

In tandem with the demographic shift, the central government also has Shanghainese in its sights with a raft of pro-Putonghua policies. Continuing the aims begun by Sun Yat-sen and the nationalists who deposed the empire in 1911, today's leaders have their hearts set on nation building.

In the third century BC, the great tyrant Qinshihuang forced all officials and scholars to use the same system of writing. Today, the vast nation is working towards a further unification - one spoken language.

"The decline and disappearance of dialects is a necessary part of progress. To achieve a unified country and harmonious society, we have to have a common language," says Zhang Bin, a veteran member of the Shanghai City Language Working Committee, which is responsible for implementing central government policy.

The universal adoption of Putonghua is enshrined in the constitution. In the early 1980s, the Shanghai government started working towards such an end with a complete ban on Shanghainese in all schools from kindergarten up.

Ten years later, it was the turn of the media. Popular television soap operas in Shanghainese disappeared in the early 1990s. The only broadcasting permitted in the language today is traditional artistic performances - and some radio chat shows. Last December, a Tom and Jerry cartoon dubbed in Shanghainese was banned to underline the government's resolve.

In 2001, legislation was passed to virtually eliminate Shanghainese from official life. All civil servants - from train-ticket sellers to policemen - are required to use Putonghua in their dealings with the public. A continuous barrage in the state-controlled media urges citizens to speak more of the national language.

In a recent campaign, attending pronunciation classes was made mandatory for Shanghai officials, ostensibly in preparation for the city's 2010 Expo.

Together, these measures have been so successful that Shanghainese is starting to disappear from its last refuge, the home. At Jinganqu Primary School teachers say many of the pupils do not speak Shanghainese with their parents because one or both are outsiders and, in some cases, no Shanghainese is spoken even when both mother and father are native-born.

"Parents often think that speaking only Putonghua will be to their child's long-term advantage," says teacher Diming.

Yet defenders of Shanghainese are mobilizing. In one of a number of similar events, academics from across the city held a conference, "Shanghainese and the Plurality of Culture," on July 4 this year, to look at ways of arresting the decline. This autumn, in a session of the city's upper house of government, Shanghai opera star Ma Lili complained that low language standards are making it hard to find enough new recruits for the opera. She called for measures to protect the language.

The media has also picked up the scent of linguistic decay. In early November, the Shanghai Times ran an article called "Nine Sins in the Decline of Shanghainese." Culprits blamed included amahs hired from other provinces, the snob value of speaking standard Putonghua, and even a rage for impersonating the heavily accented Putonghua of Hong Kong celebrities.

But not everybody is worried because not everyone believes what is happening amounts to decline. It all depends on what you mean by "decline."

At the July conference, scholar Xu Jilin complained that "high" Shanghainese, the language as it might be used by officials and academics, has all but disappeared. All that remains is colloquial street talk. "Shanghainese has often been seen as having the potential to antagonise the northern dialect," Xu said, in reference to Putonghua speakers. "In the spheres of literature, film, television and drama, Shanghainese has been smashed."

Shanghainese teacher Ruan Henghui, however, disagrees. There is no such thing as "high" Shanghainese, he says. All that exists is the stiff, formal language of the old, as opposed to the flexible language of the young. If the former disappears and the latter changes, then this amounts to evolution or progress, but certainly not decline.

"The Shanghainese that Ma Lili speaks today isn't the same as poets and scholars spoke a hundred years ago. Does that mean her language is inferior to theirs?" Ruan asks.

Nevertheless, others point out that such evolution is heading in a direction that looks suspiciously like Putonghua. As a leading figure in the movement to protect the language, Shanghai University professor Qian Nairong says many words with no direct translation into Putonghua are disappearing, along with idioms and proverbs capable of expressing nuance. "The speech of children under 15 today is filled with Putonghua words. The only way they can express themselves with precision is by speaking entirely in Putonghua," he says.

Tang Zhixiang is a native-born Shanghainese who is now researching both his mother tongue and Cantonese at Shenzhen University. Earlier this year, he asked 30 recent graduates of Fudan University to take a test in Shanghainese. The results were alarming.

"I asked them to read out a newspaper in Shanghainese but none of them could do so. They couldn't speak fluently. This situation is very serious," he says.

At the heart of the debate over whether the language is disappearing is the question of whether there is a Shanghai language. Some believe that Shanghainese - along with Cantonese, Hakka, Hokkien, Chiu Chow and all the others - is merely a variant of the same Han language spoken by the entire Han race, in the same way that the people in Singapore, Glasgow and the southern United States all speak dialects of English.

If that is true, Hong Kong may be in for a shock one day.

Not so fast, says Tang. "Regional tongues are ancient Chinese preserved at different stages of development. They are completely different from Putonghua."

"Cantonese has its own grammar and vocabulary," notes Virginia Yip, Professor of Linguistics at the Chinese University of Hong Kong. "It has it's own internal rule system that's quite different from [Putonghua] and other dialects."

Cantonese is by far in the best shape among the Chinese tongues to hold its own. The most prosperous province in China, for one, is a long way from Beijing. "Guangdong has always been less tightly controlled from the center than Shanghai," says Yip. "The government of Guangdong doesn't actively discourage Cantonese, and that's enough for it to flourish."

What this looser influence translates into is a brace of local television and radio stations in Cantonese. Tang says he is even aware of schools in the province where Cantonese remains the medium of instruction.

The language also draws support from a worldwide diaspora that is much more numerous and influential than overseas speakers of other Chinese tongues.

Most of all there is Hong Kong. With its financial and trading might, its popular films and the secure foundation for Cantonese it provides through its government, business, education and broadcasting, the territory is the force behind Cantonese today.

Rather than declining, there are even signs that Cantonese is spreading, with recent demand for classes in the language in Shanghai.

As for Cantonese's sickly northern cousin, defenders of Shanghainese are now looking to Guangdong - demanding television channels devoted to their language, and even its reappearance in schools. Their alternative vision for tomorrow's China is one where the national language does not threaten regional dialects' right to exist.

"In the reign of the Qing emperors, Kangxi and Qianlong, there were also many local languages, and China was both stable and powerful," says Zhou Zhenhe, professor of history at Fudan University. "My opinion is that the existence of dialects need not threaten our country's strength and unity."