Actors in this weekend’s production of “Waiting for Godot” at the Royal Dramatic Theater in Stockholm performed neither in the classic play’s original English nor in Swedish translation. Rather, they were speaking Yiddish, a language spoken by few Swedes but increasingly cherished by many. The Yiddish version of Samuel Beckett’s classic absurdist play, translated by Shane Baker, premiered in 2013 through the New Yiddish Rep, a theater company in New York City, under the direction of Moshe Yassur, a Holocaust survivor whose career in Yiddish theater dates to his prewar childhood in Romania. It has toured as far afield as...