The financial industry relies greatly on information technology (IT) because of its work with immaterial goods. Nowadays, most information collected by a financial institution is usually stored in a central data warehouse system. This central financial data warehouse (FDWH) is permanently under construction. Requirements from all over the bank have to be met by FDWH projects in an ongoing process. These requirements need to be communicated to the FDWH project team to do implementations properly throughout the system landscape. Especially the creation of extraction, transformation and loading (ETL) processes depends on the project team’s communication ability and given communication barriers. Enhancing recent research in FDWH a theoretical efficiency model based on philosophy of language and project management fundamentals is built in this paper. The conceptualization of information systems development projects as language communities is an important presumption for this theoretical model. Suggestions derived from this model lead project managers of FDWH projects to more appropriate decisions keeping efficiency drivers in communication in mind.