Sojourners and Her Portmanteau, in repertory at the New York Theatre Workshop, want to be heard. Mfoniso Udofia’s plays, conceived of as part of a nine-play multigenerational chronicle (of which five have been written) of the Nigerian-American Ufot family, saunter from moment to moment, expanding each dramatic beat to examine it with microscopic curiosity. Though the result, as shaped by director Ed Sylvanus Iskandar and dramaturg Janice Paran, is often excruciatingly dry, the plays demand a witnessing of their American immigrants’ stories.