A visual display system for the teaching of intonation to deaf persons

Deaf speakers frequently experience difficulties in generating a proper intonation. For this reason attempts have been made to improve their intonation with the help of visual aids that display the pitch of speech. This paper deals with the development of a visual intonation-display system for the teaching of intonation to deaf persons. In this system, visual feedback of intonation is given as a continuous representation of the pitch contour containing only the perceptually relevant aspects of the intonation pattern. The course of the pitch contour is approximated with the help of a small number of straight lines resulting in a so-called stylized pitch contour. Furthermore, correct positioning of the pitch movements with respect to the vowel onsets is crucial for proper intonation. Vowel onsets are therefore measured and displayed. First, a description of the system will be presented. Second, as the speech-processing algorithms for speech from hearing persons speaking fluently are used, the applicability of these algorithms to speech used in speech-training situations of deaf persons is tested. The results showed that the pitch-measurement algorithm and the algorithm for stylization performed well. The vowel-onset-detection algorithm, however, did not work adequately. The results are discussed in terms of the development of an instructional program for the teaching of intonation to deaf persons.