Originally intended for use with the hearing impaired (Kewley-Port, 1994), ISTRA has also been used in training programs with normal-hearing, misarticulating and developmentally delayed children and adults. ISTRA training has been shown to be clinically effective to improve speech intelligibility. (Kewley-Port, Watson, Elbert, Maki, and Reed, 1991).

ISTRA is not a subtitute for a teacher of the deaf or speech-language pathologist, but is a training aid designed for use by clinicians and other professionals. It provides client-tailored, long-term drill sessions with detailed records of progress.

The software package employs several levels of competitive games as well as eye-catching graphics to enhance motivation during speech training drills. Thus, ISTRA permits the implementation of drill sessions for several clients under the supervision of a single clinician.

ISTRA uses speaker-dependent automatic speech recognition to provide individualized speech practice using phonemems, whole words and phrases (Anderson and Kewley-Port, 1995).

Feedback to clients is based on the quality of the client's production and has been shown in research to correlate with SLP judgments. (Watson, Reed, Kewley-Port, and Maki, 1989). The feedback about speech quality is immediate and motivating such that the client produces vocabulary items at a very rapid rate.

Partial list of ISTRA peer-reviewed research publications.

Anderson, S. and Kewley-Port, D. (1995). Evaluation of speech recognizers for speech training applications. IEEE Transactions on Speech and Audio Processing,Vol. 3, No. 4, 229-241.

Kewley-Port, D. (1994). Speech Technology and Speech Training for The Hearing Impaired. The Journal of the Academy of Rehabilitative Audiology, (Monograph), XXVII, 251-265.

Kewley-Port, D., Watson, C.S., Elbert, M., Maki, D., and Reed, D. (1991). The Indiana Speech Training Aid (ISTRA) II: Training curriculum and selected case studies, Clinical Linguistics and Phonetics, 5, 13-38.