Rhythmic characteristics in aging: A study on Zurich German

Abstract

Age-related changes in speech production influence both speech segmental and suprasegmental characteristics. Previous research focussed on changes in voice quality, vowel formant patterns, f0 and speech rate due to aging but only little attention has been paid on speech rhythm (durational and dynamic). In this study we analyzed the segmental durational variability as well as the syllabic intensity variability between 60 Zurich German speakers ranging in age between 20 and 81 years. Speakers read 90 sentences in Zurich German. Between-speaker durational variability across age was quantified through a variety of different rhythmic variables (%V, ΔCLn, ΔVLn, rPVI-C, nPVI-V, %VO, varcoVO, nPVI-VO, ΔPeak, varcoPeak, and nPVI-Peak). Intensity variability was computed by taking the standard deviations, variation coefficients and PVIs of average syllable intensity and syllable peak intensity values across sentences. Results based on durational measurements show that with aging there is an increase in %V and r-PVI-C. Aged voices also present lower variability in the consonantal and especially in the vocalic intervals (nPVI-V and ΔVLn). We argue that changes in the physical characteristics as well as in the neural control mechanisms of the articulators might play a significant role in age-related rhythmic changes.