speak in tongues
To appear to chant or babble in a language one has never spoken or studied, especially as a part or because of religious worship. As a part of the spectacle, the traveling preacher had a paid assistant start speaking in tongues during his ceremony to convince people of his legitimacy.
speak in tongues
speak in an unknown language during religious worship. Speaking in (or with) tongues is a phenomenon known more formally as glossolalia , which is regarded by some as a gift of the Holy Spirit. The Bible records that the apostles demonstrated this ability (e.g. Acts 10:46, 19:6), and it is a component of present-day charismatic Christian worship.