EVERY two weeks a language disappears. By 2100 nearly half of the 6,000 spoken today may be gone. Migration, either between countries or from the countryside to cities, is one reason: though new arrivals generally stick with their mother tongue, at least at home, their children rarely do. The dominance of English is another. But one tongue bucking the trend is Romani, spoken by 4m of the roughly 11m Roma (gypsy) people worldwide. Its health attests to the importance of language in shaping identity.

Unlike most languages, Romani has no country to call home. Its roots lie in India, but since the 10th century its speakers have scattered and kept moving. One result is that they are everywhere a linguistic minority. Another is that 150 different dialects are in use. “Anglo-Romani”, spoken in Britain, differs widely from dialects in France, Bulgaria and Latvia. One Roma man in New Zealand speaks a dialect previously only heard in Wales.

The 290,000 native Swedish speakers in Finland show no signs of dropping their language—but it is their country’s second official one, compulsory in all schools and spoken by 9.5m Swedes next door. Irish hangs on partly because of government spending on translating road signs and documents, broadcasting, teaching and extra marks for brave students who use the tongue in their final school exams.

But without a government to champion it, Romani is used mostly in the home. Academics and linguists have written it down and tried to standardise it, but many of those who speak it do not read it. America printed a Romani guide to its 2000 census form, but that is a rarity; it almost never features in official documents.

The lack of texts complicates attempts to teach it formally. Roma Kulturklass, a Swedish Romani-language school, is one of a handful in the world. Its 35 pupils study everything except Swedish and English in both Romani and Swedish. But with few textbooks, says Angelina DimiterTaikon, the head teacher, staff must make do with their own translations.

All this should mean Romani is on its deathbed. But its apparent weaknesses—its minority status and scattered speakers—are now what sustains it. One reason is its usefulness as a method of private communication for an oppressed people. It comes into its own when the police come to evict Roma from settlements, says Damian Le Bas, a British Roma and writer. Around 20,000 Roma migrants were evicted from camps in France last year, according to the Human Rights League, a charity.

Despite all those dialects, Romani also allows Roma of different nationalities to communicate. Where repression was particularly fierce, immigration is even dragging it back from the edge of extinction. Fewer than 1% of the 750,000 Roma in Spain speak Romani, partly because the language was banned in the 18th century. But Romani speakers from eastern Europe are leading a revival.

Like many pursuits with sizeable but thinly spread support, Romani-speaking is boosted by the internet. Young people are improvising, finding ways to write text messages and site comments in Romani, says Yaron Matras of Manchester University. The growth of evangelical Christianity among the Roma provides another venue for the tongue. Shaun and Shelley, an English Roma and Irish traveller in Blackpool, started to learn it when eastern European migrants came to their church in 2001. Romani “came back with the Gospels,” says Shelley. Such fervour will help it thrive.