Reading speeds for visual speech displays

Design criteria for a visual speech display system for the deaf are being investigated. Of particular interest is reading speed for displays of the type that could be produced by an automatic speech recognition device. An adaptive procedure has been developed for measuring reading speed at a prescribed level of performance (e.g., 70% of displayed sentences interpreted correctly). This technique has been used in measuring reading speed as a function of sentence length, (3, 6, or 12 words), display format (stationary, flowing, accumulative), and mode of representation (Standard English text, phonetically based symbols). Extremely high reading speeds (>500 words/min) were obtained using standard English text and very short sentences. Reading speeds comparable to normal speech rates were obtained with a simple, phonetically based representation and moderate sentence lengths (e.g., 6 words/sentence). Experiments are currently in progress on the effects on reading speed of eliminating word boundaries and adding...