Debates about new technologies, such as crop and food genetic modification (GM), raise pressing questions about the ways ‘experts’ and ‘ nonexperts’ communicate. These debates are dynamic, characterized by many voices contesting numerous storylines. The discoursal features, including language choices and communication strategies, of the GM debate are in some ways taken for granted and in others actively manipulated by participants. Although there are many voices, some have more influence than others. This study makes use of 50 hours of in-depth interviews with GM scientists, nonexperts, and other stakeholders in the GM debate to examine this phenomenon. We uncover rhetorical devices used by scientists to characterize and ultimately undermine participation by non-experts in areas including rationality, knowledge, understanding and objectivity. Scientists engage with ‘the public’ from their own linguistic and social domain, without reflexive confirmation of their own status as part of the public and the citizenry. This raises a number of interesting ironies and contradictions, which are explored in the article. As such, it provides valuable insights into an increasingly important type of discourse.