LAST year a parody video appeared in China making fun of an awful shampoo commercial featuring Jackie Chan. In both versions, the martial-arts star uses the word duang to describe bouncy hair; in the spoof he keeps repeating the syllable, before suggesting the product is fake.

Thanks to the video, Mr Chan’s neologism (best translated as “boing”) set off a storm of online metalinguistic analysis, as David Moser describes in his monograph on the Chinese language, “A Billion Voices”. Which of the four tones in Mandarin should the new word be assigned? Was it even Mandarin, given that duang, though pronounceable in that language, is not part of its standard phonology? After all, Mr Chan is from Hong Kong, where Cantonese is the native tongue. And then how should it be written? Netizens took the two characters of Mr Chan’s stage name, Cheng (“become” or “accomplish”) and Long (“dragon”), and stacked them one above the other to create a new character. Brilliant. Yet it bred another problem. Two written forms exist in the Chinese-speaking world. In the 1950s the mainland adopted a “simplified” system (all things are relative). But in Hong Kong and Taiwan, the traditional, “complex” characters are still used. Before you could say duang, Mr Moser relates, a complex version of the character sprang up online, too.

The episode reflected a struggle with language that has plagued Chinese reformers for over a century. When a republic was declared in 1912, there was no common spoken language in China. Yes, imperial officials had communicated in a tongue used by the elites in Beijing. But the rest of the vast country was linguistically fractured. Experts today identify half a dozen mutually unintelligible language groups spoken by Han Chinese, along with hundreds of dialects. (And that is before considering the languages of Tibetans, Uighurs, Mongols and many other non-Han peoples.) The lack of a common tongue has always seemed to threaten the daunting project of nation-building. Even to refer to different Chinese “languages” remains taboo—they must be “dialects”, or risk undermining the hallowed notion of “one China”.

The first committee to create a standard Chinese was convened in 1913. Many meetings later the choice fell on the Beijing vernacular as the basis. After they seized power in 1949, Mao and his fellow guerrillas (despite hailing from far-flung regions) retained this form, calling it putonghua, or “common language”. His enemies in Taiwan did so too, even though the island’s own dialects are very different from Beijing’s. Faraway Singapore adopted it as one of its “mother tongues”.

Mandarin is now challenging English as the most used language in the world. Yet for all that, it is artificial, with a built-by-committee feel—the vocabulary, grammar and even accent of the Beijing dialect have all been sanitised. Its spread across China is backed by coercion, its use enshrined in the constitution. In 2000 a law signed by the then-president, Jiang Zemin (a heavily accented speaker), linked putonghua to state sovereignty and socialist progress. Since the mid-1990s teachers as well as broadcasters have had to sit proficiency tests—presenters are fined for using the wrong tone. Even though Mao from Hunan and Deng Xiaoping from Sichuan had famously thick accents, edicts used to assert that actors should portray the Communist greats speaking putonghua (imagine Lyndon Johnson with the accent of an NPR presenter). The rules are now only a bit more relaxed.

Yet when loopholes allow local dialects on air, such as in traditional opera, they are exploited. In the lucrative children’s market, “Tom and Jerry” was dubbed into the Shaanxi, Henan, Hubei and Shanghai dialects until banned—a cat-and-mouse game between local outlets and the regulator, as Mr Moser puts it.

And while many local Chinese dialects and languages—Hakka, for instance—are losing ground in the face of a pro-putonghua policy, others have the scale and prestige to hold their own. In 2010 in Guangdong, which has 60m Cantonese speakers, thousands took to the streets over a proposal to cut Cantonese from broadcasts. In Shanghai popular comedians help stem the decline in the use of Shanghainese. And exploding social-media use gives flabby dialects needed exercise. Hip-hop is recorded in the Chongqing and Changsha tongues. Fans even got together to record “Let It Go”, a song from “Frozen”, a Disney blockbuster, in 25 dialects other than Mandarin.

Some bureaucrats, recognising the tragedy of losing local variants, now urge their protection, along with endangered languages of minority ethnic groups. Last month an education-ministry official opined that learning Mandarin didn’t have to be at the expense of dialects, and that studying multiple languages could even be good for children’s development.

A new rival?

As for Mandarin itself, the once-artificial construct is now showing signs of becoming a living, protean thing—witness the fun around duang. That speaks to its success. But its shortfalls are also striking. The education ministry says that 30% of the population in 2014, or roughly 400m, still could not speak standardised Mandarin, while only a tenth of those who could spoke it properly.

Meanwhile, Mandarin’s supremacy is still being challenged, above all in Hong Kong. There, resentment at the spreading use of putonghua is growing. Indeed, since protests two years ago—partly in defence of a local Hong Kong identity in the face of mainland rule—Jette Hansen Edwards of the Chinese University of Hong Kong reports a sharp increase in the number of Hong Kong people who believe the local form of English, jokingly called “Kongish”, is a unique variety. In other words Hong Kong English appears to be turning into another dialect spoken by Chinese—a means of asserting a separate identity from the mainland. As Mr Moser says, a shared language does not imply a shared vision. China’s quest for national unity has a lot further to go.