IF YOU take the subway around New York, you can sometimes hear groups of young Jewish women chatting quietly, their hair covered. At a distance, it sounds like they’re using German, perhaps Hebrew. In fact, they’re speaking Yiddish, a language once spoken by over 10m people. The wars of the 20th century changed that; barely a million speakers remain. But for all the catastrophes perpetrated against its speakers, Yiddish has endured. In fact, it is undergoing a renaissance.

First spoken by medieval Jews living on the Rhine, it is thought that Yiddish grew out of German (though linguists such as Paul Wexler have offered contrasting theories). It quickly came to embody a distinct Jewish identity: written in the Hebrew script, it shares many terms with Hebrew. Its Eastern European variety—where most Yiddish-speakers once lived—also borrows from local Slavic languages. Práven, a word derived from the Slavic verb “to celebrate”, can be used in Yiddish to denote any happy occasion. This diversity gives Yiddish an incredibly subtle vocabulary. The language has three different words for “important” one each from German, Hebrew and Slavic (the Hebrew-derived term is associated with human or social importance, while the Slavic word has a more intimate tone). This vibrancy, moreover, helped spread Hasidism, a Jewish revival movement which enthusiastically used Yiddish in its religious writings.

But Yiddish did not cower away from modern life. By 1850, a lively secular Yiddish literature had emerged. Authors like Mendele Mocher Sforim and Sholem Aleichem wrote about the problems of contemporary Jewish life such as poverty, anti-Semitism and religion in a changing world. Their stories featured a swarm of memorable characters: petty thieves, itinerant musicians and Tevye the Dairyman, later immortalised in “Fiddler on the Roof”. Yiddish was also used for political purposes. Early 20th-century Jewish socialist organisations like the Bund, popular throughout Eastern Europe, encouraged education in Yiddish. They did this in opposition to Zionists, whose support for Hebrew and emigration to Palestine the Bundists saw as impractically “utopian”.

But for all its wealth, much of Yiddish culture was destroyed in just a few years. Before the second world war, the Yiddish population stood at around 13m; the Nazis murdered 6m Jews, 85% of whom spoke Yiddish. Many of the survivors fled to Palestine, but the new Israeli state discouraged Yiddish: Zionists regarded Hebrew as the sole language of the Jewish people. Yiddish was rejected for its associations with the downtrodden victims of the Holocaust. Jewish migrants to America, meanwhile, shrugged off their Yiddish to better assimilate.

Following the second world war, Yiddish seemed doomed, but it has made a comeback. In 1978, Issac Bashevis won the Nobel prize for literature, prompting a reappraisal of writing in Yiddish more generally. The supremacy of Hebrew in Israel—only 2% of Israelis speak Yiddish—also made Yiddish seem less threatening to Hebrew speakers. Nowadays, many Jews lap up the masterpieces of Yiddish literature both in its original form and in translation. In 2016, young fans of Yiddish met near Montreal to celebrate Aleichem’s work. Artists were encouraged to practise writing, while the festival also offered workshops on Yiddish theatre. Many universities, including Oxford and Columbia, offer courses in classic Yiddish literature.

Traditional Yiddish music is being revived, too. Musicians like Daniel Kahn recall the radical songs of the Bund. In one tune, Mr Kahn condemns “foolish little Zionists” who go to Jerusalem rather than “stay in the Diaspora and fight for our liberation.” Adrienne Cooper, a Yiddish singer who died in 2011, produced an album of music sung during the Holocaust. In one song, Ms Cooper urged the Jews to make “the fascist tremble”. Elsewhere, she sang a moving lullaby written in the Lodz ghetto. “Baggage in hand, our home in ashes,” she sang, “we are setting out, my child, in search of luck.”

Not that lovers of Yiddish only look backwards for inspiration. Mr Kahn, for example, has covered Leonard Cohen’s “Hallelujah” in Yiddish. Anthony Russell, a singer, combines Yiddish folk songs with African-American spirituals. Writers like Dov Ber Kerler have published several books of contemporary Yiddish poetry. In 2016, Yisroel Nekrasov published “Burnt-Down Cities”, a dark collection of poems about life in St Petersburg. In 2009, supported by UNESCO, several Yiddish writers met in Jerusalem to recite their work. “Vaybertaytsh”—sardonically named after the religious texts men wrote for women in Eastern Europe—is a podcast for Yiddish-speaking feminists.

And despite its radical socialist past, some of the most innovative work in Yiddish now comes from the ultra-Orthodox community. In these close-knit groups, families have preserved the Yiddish of their forefathers. Lipa Schmeltzer (pictured), an ultra-Orthodox Jew from New York State, combines club beats with lyrics about Jewish rabbis. This unusual mix has proved immensely popular: Mr Schmeltzer has released over ten albums and is known as the “Hasidic Lady Gaga”. Last year, Mr Schmeltzer was chosen to sing “God Bless America” at the inauguration of a Jewish judge in New York. Naturally, the words were in Yiddish.

That figures like Mr Schmeltzer are New Yorkers is unsurprising. With over 100,000 Yiddish speakers, the state has proved a reliable protector of the language. In some ultra-Orthodox communities, like New Square, 93% of the population speak Yiddish. The Yiddish Forward, founded in 1897, is still publishing articles from its offices in New York’s Lower East Side. Admittedly, many New York Jews have forgotten their Yiddish, but the language still makes its presence felt through several words and expressions. For as long as New Yorkers schlep, or have chutzpah, Yiddish will live on—even if the villages that bore these words turned to dust long ago.