The eleventh annual edition of this gathering focusses on the literary culture of contemporary Africa, with the Nigerian-born writer Chimamanda Ngozi Adichie co-curating special programs with László Jakab Orsós, the festival’s director. More than a hundred writers from thirty countries are participating, including Edwidge Danticat, Mona Eltahawy, Tom Stoppard, and Alain Mabanckou. (For a complete list of events, visit penworldvoices.org. May 4-10.)