Evaluation of a Mobile Multimodal Application Design - Major Usability Criteria and Usability Test Results

Mobile broadband internet access and powerful mobile devices make interesting and novel communication applications possible (e.g., recently emerging VoIP applications). Additionally, speech recognition has matured to the point that companies can seriously consider its use. We developed a distributed framework that enables multimodal user interfaces with speech recognition (dictation and command/control) on any type of mobile device. But do users already accept speech as additional input modality, and if so, which usability challenges arise when developing multimodal applications? This paper presents the results from usability tests that we conducted with a mobile multimodal e-mail and contact application. Based on the results we point out major usability criteria that need to be met in developing mobile multimodal applications.