Over the last decade voice technologies for telephony and embedded solutions became much more mature, resulting in applications providing mobile access to digital information from anywhere. Both a growing demand for voice driven applications in many languages and the need for improved usability and user experience now drives the exploration of multi-lingual speech processing techniques for recognition, synthesis and conversational dialog management. In this overview article we discuss our recent activities on multi-lingual voice technologies and describe the benefits of multi-lingual modeling for the creation of multimodal mobile and telephony applications.