I develop a case study of demonic glossolalia (speaking in tongues) for its cues in conveying religious commitment among a congregation of Apostolic Pentecostals. From the perspective of signaling theory, costly or hard‐to‐fake signals may convey psychological dispositions of members and would‐be members toward an inclusive community. I utilize signaling theory in a broader systems approach to make sense of an incident of speaking in tongues that a congregation decries as demonic. To facilitate this interpretation, forms and motivations of glossolalia—the sine qua non that one has accepted Jesus as personal savior—are described and examined, including examples of calm and excited “Holy Ghost” and “backslider” and “mistaken demonic” glossolalia. To an outsider, some of the differences among these signaling modes may be difficult to distinguish, but the underlying religious and family dynamics provide insights as to how church members make distinctions they attribute to the spiritual “gift of discernment.” This approach promises to make unique contributions toward understanding the implicit folk psychologies of practices that, according to Pentecostals, mark them as “weird” or “odd.”