It has been known that listeners react subjectively to numerous aspects of a person’s speech. Listeners attribute different sorts of social/psychological attributes to a speaker depending on that speaker’s dialect, delivery style, and voice quality. The present study examines the subjective reactions of persons listening to witness testimony, in particular, courtroom testimony given in Spanish and interpreted in English. The study shows that one aspect of a witness’s speech, politeness, plays an important role in the formation of impressions of witnesses. Furthermore, it is demonstrated that the court interpreter has the power to alter the politeness of a witness’ testimony, and in doing so, influences the impression that mock jurors have of that witness.