A temporal dimension must be present in interactions between agents that must cooperate in continuously changing environments. In this paper, we present the definition of a temporal agent communication language. This language uses a sophisticated communication model based on the speech act theory. It is the component of a more important research dealing with the study of temporal reasoning in multi-agent systems. This work takes place, also, in the building of an interaction toolbox with temporal abilities in the context of a Multi-Agent System Platform in construction in our laboratory.