Abstract
This investigation examines the discursive history and contemporary courtroom discourse of expert witnesses in Anglo-American courts, incorporating the methods of Michel Foucault into a Critical Discourse Analysis framework. The history of experts is marked by a profound discontinuity in the role of experts, during the late medieval period, with experts relegated to a witness role instead of a juror role - that of the privately knowledgeable investigator - they previously held. Examination of the discourse of contemporary experts in three high-profile US trials documents a different witness status for experts along three parameters: amplification of question responses; the use of the contrastive discourse marker well to express professional disagreement with their interlocutors; and the embedding of professional practices into so clauses. These parameters stand in sharp contrast to ordinary witness discourse. The study concludes with a discussion of the stakes in legal control of expert witnesses including asymmetrical access to experts by economic status, the possible suppression of some expert testimony by recent US Supreme Court decisions, and the hierarchicalization of expert knowledge.