AbstactThere is currently no effective way for the Deaf to communicate in sign language using mobile devices in South Africa and many Deaf people use their mobile phones for communication; while they prefer to converse in South African Sign Language (SASL). This study explores how to implement a health communication aid on a mobile phone to support a Deaf person when visiting a public hospital pharmacy. The aim is to prevent problems of non-compliance to treatment due to poor communication between a Deaf patient and a pharmacist. The risk of miscommunication is high for Deaf patients living in South Africa who communicate in SASL since most government pharmacists and public workers in general cannot communicate in SASL. This reseach describes a multi-disciplinary collaboration towards iterative development of a mobile communication tool to support a Deaf person in understanding usage directions for medication dispensed at a pharmacy. We are improving usability and correctness of the user interface. The tool translates medicine instruction given in English text to South African Sign Language videos, which are relayed to a Deaf user on a mobile phone. Communication between pharmacists and Deaf patients were studied to extract relevant exchanges between the two users. We incorporated the common elements of these dialogues to represent content in a verifiable manner to ensure that the mobile tool relays the correct information to the Deaf user. Instructions are made available for a Deaf patient in sign language videos on a mobile device. A pharmacy setup was created to conduct trials of the tool with groups of end users, in order to collect usability data with recorded participant observation, questionnaires and focus group discussions. Subsequently, pre-recorded sign language videos, stored on a phone's memory card, were tested for correctness. Lastly we discuss the results and implications of the study and provide a conclusion to our research.