“Interface between Yiddish and English was my second line of argument. The influx of Yiddish into London and New York at the end of the nineteenth and start of the twentieth centuries, initially so alarming to protectionists like Henry James and Henry Adams, was soon welcomed by stylists like H.L. Mencken. How much poorer English would be without the schlemiel and his bagel, without the chutzpah to kvell, kibitz and kvetch. By that time, the enlivening effects of Yiddish had inspired the 1960s motto, “Dress British, think Yiddish.” Professional comedy was then about 75% Jewish, driving Yiddish ironies into the mainstream, and at culture’s other extreme, the Holocaust was penetrating historical consciousness, with Yiddish as its major language of witness. The relatively large number of Yiddish speakers in Montreal, including Holocaust survivors and their children, was a major point in favor of its local relevance.”
Source: How is Yiddish Doing?