It’s a fool’s errand to try to pin down Samuel Beckett’s most radical theatrical experiment, but the 15-minute monologue Not I makes a list of the top five or ten. An old crone (the playwright’s description), who has been mute most of her life, suddenly starts babbling at dizzying speed about mundane incidents of enigmatic import. The audience sees nothing of her but her mouth. A shadowy listener responds only in shrugs. Written for Billie Whitelaw, the play was originally performed by Jessica Tandy in New York in 1972. In this newly commissioned adaptation, the Greek avant-garde composer Zesses Seglias and the stage director Stavvos Stroumpos attempt to render “the Beckettian sonic and semantic ‘abyss’” by means of “two bodies in vocal and spatial counterpoint.” Come again? —Matthew Gurewitsch