Pitch Adaptive Time-Rate Expansion For Enhancing Speech Intelligibility

Many factors can affect an individual's ability to correctly discern speech signals. Among these factors are background noise and conflicting information signals. Some research studies have suggested that time-rate expansion of speech signals can result in increased intelligibility for certain population segments. However, little work has been done to quantify the effect of moderate levels of speech expansion under adverse listening conditions. This paper describes a pitch-adaptive implementation for generating high-quality, time-expanded speech. Clinical tests on 16 subjects using monosyllable words with additive noise show an overall improvement in intelligibility for the bl speech rates tested. The best results were achieved at an expansion rate of 30%, where the subjects showed an average improvement of 29.1% when compared with no time expansion. (C) 1996 Acoustical Society of America.