Differential patterns of Voice Onset Time in English plosives produced by Urdu–English bilingual speakers with Dysarthria

This study investigates Voice Onset Time (VOT) in Urdu - English bilingual speakers with and without dysarthria, with a specific focus on differential vulnerability of positive and negative VOT. Acoustic analyses were conducted on English word-initial plosives produced by 30 speakers with dysarthria and 30 neurologically healthy controls. Non-parametric analyses revealed that dysarthria-related timing disruptions were concentrated in pre-voiced lenis plosives (/b, d, g/), while voiceless plosives (/p, t, k/) showed no consistent group-level differences. Subtype analyses indicated distinct pre-voicing patterns across flaccid, spastic, ataxic, and mixed dysarthria, with the largest effects observed for velar stops. These findings suggest that dysarthria selectively compromises the laryngeal - supralaryngeal coordination required for sustained voicing during closure. The results highlight negative VOT as a sensitive acoustic marker of dysarthric impairment and underscore the value of mechanism-focused, distribution-sensitive analyses in clinical phonetics.