A descriptive study on the acoustic and kinematic characteristics of internal open junctures: Implications for highly intelligible individuals with Parkinson’s disease

Abstract

This study extends previous work on the acoustic characteristics of ambiguous sentences for male speakers with Parkinson’s disease (PD) [Kuo, JASA 148(4), 2583 (2020)] with additional data. Specifically, the purpose of this study is to further understand acoustic and articulatory characteristics of internal open junctures for speakers with PD. Internal open junctures consist of set strings of phonemes that are phonetically and/or semantically ambiguous when there exist two or more ways to segment the phoneme strings [Lehiste, Phonetica 5(Suppl. 1), 5–54 (1960); Fisher & Logemann, Q. J. Speech 53(4), 365–373 (1967)]. As a part of a larger study, speech acoustic output and tongue kinematic data from four male speakers of American English with PD and two neurologically healthy males were captured simultaneously using 3D electromagnetic articulography. Vocalic segments of internal open junctures were identified acoustically from ambiguous sentence productions, in which the internal open junctures were obtained in pairs, with each phoneme string contributing to two different word combinations. The second formant (F2) and tongue kinematic trajectories are compared for these pairs. It is hypothesized that for the same phoneme string, varied linguistic boundaries elicit differences in tongue trajectory patterns and F2 changes in duration and speed.