What can I say?: addressing user experience challenges of a mobile voice user interface for accessibility

Voice interactions on mobile phones are most often used to augment or supplement touch based interactions for users' convenience. However, for people with limited hand dexterity caused by various forms of motor-impairments voice interactions can have a significant impact and in some cases even enable independent interaction with a mobile device for the first time. For these users, a Mobile Voice User Interface (M-VUI), which allows for completely hands-free, voice only interaction would provide a high level of accessibility and independence. Implementing such a system requires research to address long standing usability challenges introduced by voice interactions that negatively affect user experience due to difficulty learning and discovering voice commands. In this paper we address these concerns reporting on research conducted to improve the visibility and learnability of voice commands of a M-VUI application being developed on the Android platform. Our research confirmed long standing challenges with voice interactions while exploring several methods for improving the onboarding and learning experience. Based on our findings we offer a set of implications for the design of M-VUIs.