Designing visual Speech Training Aids for Hearing Impaired Children

Lack of auditory feedback for hearing impaired children leads eventually to a speaking disability in them. Hence, hearing impaired children are unable to speak, in spite of having proper speech production mechanism. Even if the hearing impaired child tries to speak by visualizing lip movements, his articulation, accuracy, stress and intonation patterns are affected, since vowels & consonants with tongue movement hidden in the mouth are not distinguishable to him and neither speech intensity or pitch variations are understood. Depending on the severity of the hearing impairment, either auditory, or tactile or visual feedback could be provided to the hearing impaired individuals. Speech-training systems can be designed based on feedback of acoustic parameters such as speech intensity, fundamental frequency, spectral features, or feedback of articulatory parameters such as voicing, nasality, lip and vocal tract movement. Using computer based speech training aids, for the hearing impaired children, the auditory feedback mechanism can be replaced by a visual representation of important acoustic parameters of speech such that as a child speaks he would be able to evaluate and correct his utterance/pronunciation based on expected and actual parameters that are displayed to him. This paper discusses about the speech training aids and the possible speech processing that can be done to obtain visual feedback for the hearing impaired children so that they get an opportunity to learn, speak and communicate properly through these aids. Also, an implementation using LPC analysis of speech is done to obtain vocal tract shape of children speaking vowels from various age groups so that it could be used as visual feedback to design a visual aid.