We present in this poster our work on a User Interface Markup Language (UIML) vocabulary for the specification of device- and modality independent user interfaces. The work presented here is part of an application-oriented project. One of the results of the project is a prototype implementation of a generic platform for device independent multimodal mobile applications. The poster presents the requirements for a generic user interface description format and explains our approach on an integrated description of user interfaces for both graphical and voice modality. A basic overview of the vocabulary structure, its language elements and main features is presented. Categories & Subject Descriptors: H.5.2 [Information Interfaces and Presentation (e.g., HCI)]: User Interfaces ? graphical user interfaces (GUI), interaction styles, voice I/O. D.3.3 [Programming Languages]: Language Constructs and Features ? Data types and structures, frameworks. General Terms: Design, Experimentation, Hu...