Abstract — Research in mobile service robotics aims on development of intuitive speech interfaces for human-robot interaction. We see a service robot as a part of an intelligent environment and want to step forward discussing a concept where a robot does not only offer its own features via natural speech interaction but also becomes a transactive agent featuring other services ’ interfaces. The provided framework makes provisions for the dynamic registration of speech interfaces to allow a loosely-coupled flexible and scalable environment. An intelligent environment can evolve out of multimedia devices, home automation, communication, security, and emergency technology. These appliances offer typical wireless or stationary control interfaces. The number of different control paradigms and differently lay-outed control devices gives a certain border in usability. As speech interfaces offer a more natural way to interact intuitively with technology we propose to centralize a general speech engine on a robotic unit. This has two reasons: The acceptance to talk to a mobile unit is estimated to be higher rather than to talk to an ambient system where no communication partner is visible. Additionally the devices or functionalities to be controlled in most cases do not provide a speech interface but offer only proprietary access. Index Terms — HCI, mobile robots, transactive systems, ambient intelligence I.