The study of conversational humor has received relatively little empirical attention with almost no examinations of the role of vocal signals in spontaneous humor production. This article reports an analysis of spontaneous humorous speech in a rural Brazilian collective farm. The sample was collected over the course of ethnographic fieldwork in northeastern Brazil, and is drawn specifically from the monthly communal business meetings conducted in Portuguese. The analyses focused on humorous utterances identified by the subsequent presence of laughter. Acoustic features of these utterances were compared to non-humorous utterances by the same speakers of similar length and immediately preceding them to look for prosodic contrasts. This corpus provided a unique opportunity for examining the way people mark their humorous productions in a non-humorous environment. Contrary to the notion that speakers must mark their production of humor in order to facilitate audience understanding, no significant marking of a joking “frame“ was detected across a range of acoustic dimensions. The only consistent difference — that the set-up and punch line segments were louder than baseline speech before it — does not well support a marking hypothesis and more likely reflects speaker adjustments to the acoustic conditions of the meeting hall. The article presents these data from the perspective of the encryption theory of humor that predicts speakers will not generally mark spontaneous, conversational humor in most contexts.