Melodic Klezmer notes float through the blistering Lithuanian winter air. A door opens near Vilnius’ old Green Bridge and a group of Jewish friends spill into the street. “Zei Gezunt,” they call to each other in Yiddish, scrolling through their smart phones as they part ways.

It is 2016. The vivacious young men and women leaving the World Jewish Congress’ International Yiddish Culture Center are speaking what is considered to be a dying language, uttering words used by their grandparents – words even their parents barely know.

More than seven decades have passed since the end of World War II and the destruction of what was once one of the centers of Jewish life in Europe, widely known as the Jerusalem of Lithuania. On the eve of the war, the Jewish community in Vilnius numbered 70,000-80,000, including an influx of refugees from Poland; across Lithuania, there were roughly 250,000 Jews. Yiddish was their native language, as it was for 11-13 million others in Europe, Palestine and the Americas.

Today, there are approximately 5,000 Jews in Lithuania, and the generation that can still recall Vilnius in its former glory as a center of Jewish culture and for whom Yiddish was their mame-loshn is nearly gone. The number of fluent Yiddish speakers in the world now barely grazes 2 million.

But as the great author Isaac Bashevis Singer remarked in 1978, upon receiving the Nobel Prize in Literature, “Yiddish has not yet said its last word.”

Yiddish is not just a language. It is the dissonant pre-jazz tempo of the flute and the snare drum, the fatty schmaltz sizzling in the delicatessen frying pan, the fantastical realities brought to life by the writers Sholem Aleichem and Yitzhak Leib Peretz. It is the legacy of the Ashkenazi Jewish culture that thrived in Eastern Europe for nearly a millennia.

And for a critical mass of Holocaust survivors in the years following liberation, it was these words and memories that empowered them to regain their lives and take back their humanity.

Yiddish is still the mother tongue for more than a million ultra-Orthodox Jews across the world. But since even before the establishment of the State of Israel – thanks to the Zionist movement’s enforcement of the newly revived Hebrew language and the ingathering of Jewish exiles from North Africa and Arab lands whose Judeo languages of their own so differed from that of Eastern European Yiddish – Hebrew has become the Jewish lingua franca.

Still, a movement has been on the rise over the last two decades, among secular and more modern streams of Judaism alike, to revive the once-vibrant Yiddishkeit culture of their Eastern European ancestors. Universities on nearly every continent offer courses in Yiddish, based on the standard set by the Yiddish Scientific Institute (YIVO), which celebrated its 90th anniversary last year, and has successful centers in New York and Buenos Aires; Yiddish theater troupes have established themselves across Israel, Europe and North America and Yiddish cultural festivals draw thousands each year.

In the year since its creation, WJC’s International Yiddish Culture Center has faced increasing demand for its special breed of interdisciplinary Yiddish education, which is geared primarily toward providing formal and informal educators with the tools to successfully pass information on to their own students. From Ukraine to Uruguay, the center has provided seminars to more than 2,000 people of all ages, teaching them not just Yiddish words, but also about the vibrant folklore, literature, music, theater, film and media produced in the pre-war heyday of Yiddish culture.

It is perhaps only natural that a Yiddish renaissance might take place in cities like New York, which has the largest Jewish population outside of Israel and where some of the greatest Yiddish theater and culture arose in the early 20th century; it is the antidote to assimilation, an expression of belonging and of reclaiming tradition. YIVO recognized this potential early on and began offering an intensive language, literature and culture program in the late 1960s well before Yiddish revivalism crept back into fashion.

But one key evidence of both the need for and the success of the Yiddish cultural revival, is that it is also taking place in the very same Eastern European streets where it was born, in places where strong communities of Jews once lived and in which only a handful now remain. For years, Yiddish was a secret language in the Soviet Union, passed down through the generations as a testament to their Jewish identity. In the late 1980s, just before the fall of the Soviet Union, young Jews began gathering underground in Moscow, holding Yiddish seminars; many of these young participants moved to Israel in the subsequent years and are living a Jewish life they once could only dream of having.

The WJC’s center and its advisory board of eminent scholars don’t expect Yiddish to become a street language again, but it is adamantly striving to ensure that the culture it imbued over 1,000 years of history is not forgotten.

Both in Israel and in the Diaspora – particularly in Eastern Europe – reviving Yiddish language and culture is crucial for regenerating the Jewish life and identity nearly obliterated in the flames of the Holocaust and subsequent decades of intermarriage and assimilation.

As the old saying goes: Di gantse velt shteyt af der shpits tsung — the whole world rests on the tip of the tongue. And if a single word can affect the world, imagine the power of an entire language.