indirect text entry using one or two keys
This paper introduces a new descriptive model for indirect text composition facilities that is based on the notion of a containment hierarchy. This paper also demonstrates a novel, computer-aided technique for the design of indirect text selection interfaces -- one in which Huffman coding is used for the derivation of the containment hierarchy. This approach guarantees the derivation of optimal containment hierarchies, insofar as mean encoding length. This paper describes an empirical study of two two-key indirect text entry variants and compares them to one another and to the predictive model. The intended application of these techniques is the design of improved indirect text entry facilities for the users of AAC systems.
indirect text entry information theory voice output communication aids (voca) speech generating devices (sgd) interface evaluation scanning