The efficiency of the development of CTS/TTS systems is influenced by the features and services of the software development tools used in the development process. A development system should be highly flexible, informative and user friendly to fulfil all or almost all the requirements the researcher could have. In this paper we present a development systenr, MVoxDev, that can provide an informative and flexible environment for the development of multilingual CTS/TTS systents. The development system gives aid to inspect and modify all the constituent parts of the CTS/TTS system as a client of the developed CTS/TTS system.