Parliamentary discourse (PD) is shaped by pre-defined rules, which may be strategically transgressed to achieve political goals. Here, we examine a relatively unique form of PD, the discourse of the ‘Shadow Assembly’, which was tasked with establishing the procedures of the new Northern Ireland Assembly (1998). Using a discursive constructionist perspective, which emphasizes the intersection between social theory and sociolinguistics, we examine how Members of the Assembly vie to discursively establish the fundamental parameters of political behaviour within the Assembly. These included address terms, speaking rights and, indeed, which language members should speak. Hence, we have a rare opportunity to examine how discursive construction mediates the future forms of interactional limits and constraints. In particular, we consider PD in a context where the rules are not pre-established and there is, moreover, a strong history of socio-political conflict. We also consider the role of culture in shaping and constituting PD.