Perceptual Evaluation of Elderly Speech by General Adults: Focusing on Speech Intelligibility, Listening Ease, and Speech Acceptability

Abstract

Objectives: This study aimed to investigate the perceptual speech characteristics of healthy older adults by comparing speech intelligibility, listening ease, and speech acceptability across speakers in their 60s, 70s, and 80s. Furthermore, the study examined the relative influence of voice quality and prosody on overall speech acceptability to provide an evidence-based foundation for age-tailored clinical interventions. Methods: Ninety healthy older speakers, equally divided into three age groups (60s, 70s, and 80s), participated by making recordings while reading a standardized reading paragraph. Twenty general adult listeners evaluated the recordings. Speech intelligibility was calculated as the percentage of correctly transcribed words. Listening ease and speech acceptability—including sub-dimensions of voice and prosody—were rated on a 5-point Likert scale. Data were analyzed using MANOVA, Pearson correlation, and stepwise multiple regression. Results: While speech intelligibility and listening ease did not differ significantly across age groups, speech acceptability significantly decreased as age increased. Intelligibility correlated with listening ease but showed no significant relationship with acceptability. Notably, the primary predictors of acceptability shifted by age: prosody for the 60s; both voice and prosody for the 70s; and voice quality exclusively for the 80s. Conclusion: The findings suggest that intelligibility and acceptability are distinct perceptual dimensions in aging speech. Clinical assessments should incorporate multidimensional measures beyond simple intelligibility. Interventions should employ age-specific strategies, focusing on prosodic naturalness for the ‘young-old’ and prioritizing voice quality for the ‘oldest-old’ to enhance social communicative competence.