The procurement of infrastructure systems is a complex domain of information which is very difficult to manage because the knowledge pieces are generated by isolated stakeholders who are also interdependent and affect each other. The interrelationship between stakeholder information which is generated as documents introduces a challenge to keep the domain knowledge consistent and integrated. Acquisition architecture frameworks (AF) are metamodels, developed to model the whole enterprise/system life cycle stages including system procurement. Our previous study analyzed the currently used AFs such as DoDAF, MoDAF and TRAK to assess their adequacy and efficiency in modelling the infrastructure projects. The results showed that many of the procurement related concerns are overlooked such as financial matters e.g. cost and revenue calculation; risk management aspects e.g. risk calculation and risk allocation; and accountability issues e.g. responsibility of the contract parties. This paper briefly introduces a method for identifying the procurement concerns and adding new viewpoints to the architecture frameworks. The conceptual definition of the new viewpoint are then used to develop a customized language for procurement of infrastructure systems. The provided method is created by adopting other relevant methods. The method shows how the metamodel (abstract syntax) and the language stereotypes (concrete syntax) are developed. The results firstly show the 18 identified viewpoints of procurement domain and then three of them are chosen to be described in this paper. The Project Organization Viewpoint and Risk Assessment Viewpoint and the models they generate are illustrated as example diagrams of this language. The developed language can be used by the domain practitioners, who are the contracting officers and procurement managers, to generate the contracting materials to facilitate the contracting process, assure the consistency of the procurement documents, giving better project outcomes.