Decision-making on issues related to interoperability can be furthered by the use of models of the organization or information system where interoperability is of concern. In order to provide decision-making support, the models should be amenable to analyses. This paper presents a modeling language specifically for interoperability issues where interoperability is defined as the probability that two more actors will be able to exchange information and use that information. The language is coupled with a probabilistic mechanism for automated interoperability assessments of the models created. The paper also presents an example of how the language can be applied.