In open heterogeneous multi-agent systems, communication is hampered by lack of common ontologies. Ontologies may differ in naming conventions, granularity and scope. In such an environment, the agents must possess the right conversational skills to effectively exchange information even when the speaker’s ontology is only approximately translatable to the hearer’s ontology. Furthermore, the agents must be able to autonomously establish an ontology translation by exchanging parts of their ontologies. In this paper, we propose a layered communication protocol in which the agents gradually build towards a semantically integrated system by establishing minimal and effective common ontologies. We tested our system, called ANEMONE, on a number of heterogeneous news agents. We show how these agents successfully exchange information on news articles, despite initial difficulties caused by heterogeneous ontologies.