Speech-based human-device interaction is booming and companies such as Apple, Google and Nuance constantly provide us with potentially new application scenarios where voice may be the control modality of choice. Appropriate methods for designing and evaluating these voice-operated applications are, however, rare. This paper reports on our attempt of combining different Language Technology Components with a web-based Wizard of Oz tool to design and prototype a list of home care and communication services. Guided by a research project that aims at providing applications optimized for seniors, we describe our planned approach of combining wizard actions with technology output in order to build and evaluate applications that use natural language as an interaction paradigm.