Building personalised synthetic voices for individuals with severe speech impairment

Abstract

For individuals with severe speech impairment accurate spoken communication can be difficult and require considerable effort. Some may choose to use a voice output communication aid (or VOCA) to support their spoken communication needs. A VOCA typically takes input from the user through a keyboard or switch-based interface and produces spoken output using either synthesised or recorded speech. The type and number of synthetic voices that can be accessed with a VOCA is often limited and this has been implicated as a factor for rejection of the devices. Therefore, there is a need to be able to provide voices that are more appropriate and acceptable for users.This paper reports on a study that utilises recent advances in speech synthesis to produce personalised synthetic voices for 3 speakers with mild to severe dysarthria, one of the most common speech disorders. Using a statistical parametric approach to synthesis, an average voice trained on data from several unimpaired speakers was adapted using recordings of the impaired speech of 3 dysarthric speakers. By careful selection of the speech data and the model parameters, several exemplar voices were produced for each speaker. A qualitative evaluation was conducted with the speakers and listeners who were familiar with the speaker. The evaluation showed that for one of the 3 speakers a voice could be created which conveyed many of his personal characteristics, such as regional identity, sex and age.