Yes, the word is a form of “recitative.”  The OED gives several definitions, one of which is “A style of musical declamation, intermediate between singing and ordinary speech, commonly employed in the dialogue and narrative parts of operas and oratorios.” A second definition is “The tone or rhythm peculiar to any language” (an obsolete use of the word). Both meanings are pertinent to the story.  First, Twyla’s story that supposedly does not have much meaning is retold again and again throughout the lives of the two characters, each time within the political context of the time, and as they retell the event, it gathers new meaning.  Thus, the meaning of the event exists in the back and forth speaking of it, the “intermediate” aspect or “dialogic” aspect of it.  Secondly, because one character is white and one black (and we don’t know which), each understanding or interpretation has a particular “tone or rhythm” particular to the “language” of the race. As enotes explains, “At one point Twyla comments on her protest sign slogan, admitting that ‘actually my sign didn’t make sense without Roberta’s.’ This may be understood as a metaphor for the idea of difference that Morrison expresses in the story. The signs or codes used to suggest Twyla’s race don’t make sense without an opposing set of signs or codes that define Roberta in contrast.”