William Ricardo Rodríguez

A prelingual tool for the education of altered voices

This paper addresses the problem of Computer-Aided Voice Therapy for altered voices. The proposal of the work is to develop a set of free activities called PreLingua for providing interactive voice therapy to a population of individuals with voice disorders. The interactive tools are designed to train voice skills like: voice production, intensity, blow, vocal onset, phonation time, tone, and vocalic articulation for Spanish language. The development of these interactive tools along with the underlying speech technologies that support them requires the existence of speech processing, whose algorithms must be robust with respect to the sources of speech variability that are characteristic of this population of speakers. One of the main problem addressed is how to estimate reliably formant frequencies in high-pitched speech (typical in children and women) and how to normalize these estimations independently of the characteristics of the speakers. Linear prediction coding, homomorphic analysis and modeling of the vocal tract are the core of the speech processing techniques used to allow such normalization through vocal tract length. This paper also presents the result of an experimental study where PreLingua was applied in a population with voice disorders and pathologies in special education centers in Spain and Colombia. Promising results were obtained in this preliminary study after 12 weeks of therapy, as it showed improvements in the voice capabilities of a remarkable number of users and the ability of the tool to educate impaired users with voice alterations. This improvement was assessed by the evaluation of the educators before and after the study and also by the performance of the subjects in the activities of PreLingua. The results were very encouraging to keep working in this direction, with the overall aim of providing further functionalities and robustness to the system.

E-inclusion technologies for the speech handicapped

This paper addresses the problem that disabled people face when accessing the new systems and technologies that are available nowadays. The use of speech technologies, specially helpful for motor handicapped people, becomes unapproachable when these people also suffer speech impairments, making the gap in the society wider for them. As a way to include speech impaired people in the technological society of today, two lines of work have been carried out. On one hand, a computer-aided speech therapy software has been developed for the speech training of children with different disabilities. This tool, available for free distribution, makes use of different state-of-the-art speech technologies to train different levels of the language. As a result of this work, the software is being used currently in several centers for special education with a very encouraging feedback about the capabilities of the system. On the other hand, research on the use of automatic speech recognition (ASR) systems for the speech impaired has been carried out. This work has focused on current techniques of speaker adaptation to know how these techniques, fruitfully used in other tasks, can deal with this specific kind of speech. The use of Maximum A Posterior (MAP) obtains an improvement of 60.61% compared to the results of a baseline speaker independent model.