Implementing linguistic text anticipation in a writing device for the disabled

Waller, Annalu

Implementing linguistic text anticipation in a writing device for the disabled

Master Thesis

1989

Publisher

University of Cape Town

Department

Department of Human Biology

Faculty

Faculty of Health Sciences

Abstract

The advent of the microcomputer has provided the severely handicapped with the means to create text. Instead of using a keyboard, the disabled typist is able to scan and select linguistic items with an appropriate input switch. The resulting communication rate is, however, prohibitively slow for writing and impractical for conversation. A variety of techniques is used to improve this rate and range from static letter matrices to more sophisticated methods in which words and phrases are anticipated. Although many anticipatory methods claim to be linguistically based, most, if not all, depend solely on letter and word frequency statistics. A series of phonological rules can be used to anticipate the letter structure of most English words. This linguistically based system reflects a degree of "intelligence" not present in other anticipatory writing systems. To evaluate and compare the new system with several existing techniques in practice, a programmable evaluation system has been developed on an IBM-compatible personal computer using the Artificial Intelligence language, LISP. Different communication strategies are transcribed into rulebases which serve as input to the software. The core program then executes the particular system under consideration. Input text can be processed in either manual or simulation mode and an evaluation report is generated when the session ends. The characteristics of efficient communication systems are introduced as a basis for this dissertation, after which the development and application of a linguistic anticipatory writing system is described. The design of the evaluation software is documented and the successful implementation of the various communication systems is discussed.