Rhetoric's primary business has always been articulation of public knowledge and public values.1 Because making of knowledge in public realm incorporates intersecting discourses of many specialized communities, it frequently necessitates translation of expert discourse into a vernacular accessible to nonexpert decision makers. Indeed, Aristotle makes it clear in both Rhetoric and Topics that one of important uses of rhetorical art is forwarding of arguments in popular terms (34). This process of transforming into language that guides human affairs has been described by Charles Bazerman and James Paradis a conversion of the hieratic discourse of expertise into the demotic discourse of everyday practice (8). A prototype of this transformation becomes available for scrutiny in presentation of expert testimony to a jury, a process that involves accommodating knowledge claims and discourse practices of a specialized community to both formal procedures of a courtroom and lay understanding of jurors. Juries are empaneled to enact values of a larger public by deciding whether and to what degree a set of evidence matches legal definitions of criminal behavior or civil liability. By deciding guilt or innocence and determining appropriate penalties, they fulfill public function of rhetoric that Bitzer describes: to establish correct judgments in practical and humane affairs by examining contested versions of truth (68). To play this role, Gail Stygall has observed, jurors become socialized as temporary members of