Monosyllabic interrogative and declarative intonation patterns in the production of speakers diagnosed with Down syndrome – a preliminary study

Abstract

The present study investigates the acoustic characteristics of Hungarian monosyllabic rising interrogative and falling declarative utterances produced by adult speakers with Down syndrome (DS). Although DS is the most prevalent aneuploid disorder, the prosodic production of this population remains a relatively under-explored field of research. In this study, monosyllabic utterances were elicited from a cohort of eight adult DS speakers (six females and two males) and eight neurotypical (female) controls. To ensure the reliability of the data, DS realizations were filtered through a perception experiment involving four evaluators, and only those items that achieved uniform categorization were subjected to subsequent acoustic analysis. Fundamental frequency (f0) contours were analyzed using generalized additive mixed models (GAMMs), complemented by a descriptive analysis of static parameters, including minimal, maximal, and mean f0. The findings reveal significant intra-speaker variability within the DS group. Notably, the data suggest that female DS speakers exhibit lower maximal f0 values while maintaining mean f0 levels similar to those of the neurotypical group, a result that diverges from certain previous findings reporting higher f0 values for DS speakers. In summary, while most DS speakers demonstrated the physiological capacity to produce distinct rising and falling f0 patterns, the systematic elicitation of this phonological contrast remains a methodological challenge that warrants further scientific investigation.