The Uzbek singer Sevara Nazarkhan pitched herself to the English-speaking world nine years ago with Yol Bolsin, an album mediated through the swirling, mystic brain of the French producer Hector Zazou. This new, self-released album, Tortadur, is acoustic, and the instruments in the indigenous backing ensemble keep their personalities pert and intact without being trimmed or swirled. The traditional tunes are slow and stirring, her voice glides forward with weights on its heels, and the elderly musicians pace patiently after her. The pace is perhaps too slow as the tracks threaten to melt together, but the decoration is subtle and lovely: The tick-tock in “Yovvoi Tanovar” is like a pencil tapped loosely on a wineglass, and Nazarkhan’s voice, swimming, swimming on, is the eternal coexisting with the temporal.