Does Native Language Matter in Perceptual Ratings of Dysarthria?

Abstract

Purpose: Despite the general agreement that dysarthria characteristics are largely language-independent, few efforts have attempted a systematic comparison across languages. To examine the role of native languages in the perception of speech characteristics of dysarthria secondary to Parkinson's disease (PD), auditory-perceptual ratings of dysarthria, and confidence level of the judgments were compared between two listener groups: language-matched and language-crossed. Method: A total of 60 listeners (35 native speakers of Korean and 25 native speakers of American English) estimated speech abnormality for 20 speech dimensions using a visual analog scale method for both language-matched and language-crossed speech stimuli. Speech stimuli were passage readings of the respective languages obtained from individuals with and without PD. Results: For speech dimension ratings, eight of 20 speech dimensions revealed significant differences in response to PD speech between the two listener groups, for most of which, language-crossed listeners' estimation was lower (i.e., more impaired) than language-matched listeners. For confidence-level ratings, language-matched listeners were less confident in the ratings of speakers with PD compared to the language-crossed listeners. Conclusions: The data support both language-universal and language-specific aspects in perceiving dysarthria characteristics, such that native language plays a role, especially when rating articulatory- and rhythmic-related characteristics. The findings are discussed with respect to the role of linguistic information, such as phonetic inventories and prosodic structures, in perceiving dysarthria characteristics.