Comparing vowel intelligibility across interactive and non-interactive tasks in disordered speech

The current study examines vowel intelligibility across interactive and non-interactive situations for individuals with dysarthria secondary to amyotrophic lateral sclerosis (PALS). The vowel space of these speakers is often characterized by centralization and lowering, negatively affecting intelligibility. In two experiments, listeners identified vowels produced by PALS in habitual speech (non-interactive), clear speech (non-interactive), and interactive matching. Clear speech and interactive matching elicited more intelligible vowels than habitual speech. Interactive matching productions were equal to or more intelligible than clear speech productions depending on vowel. These data represent a preliminary step to understanding how the dynamics of communicative interaction may shape vowel intelligibility.