Increasing the efficiency of a continuous motion alternative speech device through a higher dimensional sound space

An important area of alternative and augmentative communication (AAC) device design is the optimization of AAC devices with respect to cognitive load and mechanical efficiency in order to allow severely speech impaired (SSI) users to more readily approach natural speech rates. The University of Virginia\´s Communication Aids Negating Disabilities in Youth (CANDY) Laboratory\´s work centers on a unique AAC device which operates in a continuous "space" of speech sounds, unlike most other AAC speech devices which utilize discrete selection of symbolic units to produce speech. Previous efforts to optimize this device were based on efficient speech sound placements in a static 2-D grid. This paper will discuss a novel higher dimensional sound space for the CANDY device which reduces user motion at the cost of increased cognitive demand.