This Major Research Project (MRP) worked on the design of an extended vocabulary for use by individuals who use Augmentative and Alternative Communication (AAC) devices, which would enhance their communication capabilities in medical emergency and hospital intensive care situations. The vocabulary was derived through a study of the communication needs of users in medical situations. Individual and group interviews were conducted with ten participants – four AAC users, two caregivers, two Speech-Language Pathologists and two medical care professionals. Vocabulary suggestions obtained from them were analyzed and organized. The results provide a preliminary vocabulary and recommendations for ways in which communication by non- speaking persons in medical situations could be improved. In the next stage of this research, a hierarchical vocabulary derived from this work will be incorporated into an iPad-based commercial AAC system and its usability will be studied with the same group of users to further refine and revise the vocabulary.