In this paper we present GDialogXML, which is a new powerful modeling language for multi-modal dialog applications. In contrast to other dialog description languages (e.g. VoiceXML) GDialogXML focuses on the complete development process, covering data models, dialog flow, interaction models, and many more. It even allows for the modality-independent modeling of dialog applications. Beside some innovative features like the modality refinement procedure, a main achievement of GDialogXML is its integrating architecture.