A key problem for models of dialogue is to explain how conventions are established and sustained. Existing accounts emphasize the importance of interaction, demonstrating how collaborative feedback leads to more systematized, stable and arbitrary referential conventions. However, co-ordination in dialogue requires both co-ordination of content and of process. To investigate procedural co-ordination we report a collaborative task which presents participants with the recurrent co-ordination problem of ordering their actions and utterances into a single coherent sequence. The results provide evidence of the development of group-specific procedural conventions, resulting in elliptical utterances whose communicative meaning is determined by their sequential location within the dialogue.