Examining modality usage in a conversational multimodal application for mobile e-mail access

As Third Generation (3G) networks emerge they provide not only higher data transmission rates but also the ability to transmit both voice and low latency data within the same session. This paper describes the architecture and implementation of a multimodal application (voice and text) that uses natural language understanding combined with a WAP browser to access email messages on a cell phone. We present results from the use of the system by users as part of a laboratory trial that evaluated usage. The user trial also compared the multimodal system with a text-only system that is representative of current products in the market today. We discuss the observed modality issues and highlight implementation problems and usability concerns that were encountered in the trial. Findings indicate that speech was used the majority of the time by participants for both input and navigation even though most of the participants had little or no prior experience with speech systems (yet did have prior experience with text-only access to applications on their phones). To our knowledge this represents the first implementation and evaluation of its kind using this combination of technologies on an unmodified cell phone. Design implications resulting from the study findings and usability issues encountered are presented to inform the design of future conversational multimodal mobile applications.