Discourse repetition and phonetic reduction in a person with dysarthria secondary to Parkinson’s disease

Background: A common concern for persons with dysarthria is a difficulty in being understood. This is captured clinically using assessments of intelligibility. Any attempt to measure intelligibility must be carried out in a way that is sensitive to the phonetic variation that occurs in naturally occurring conversational speech. This article identifies examples of an interactional event known to trigger phonetic variability: discourse repetition. Method: This article is a case study of a 68-year-old male with dysarthria secondary to Parkinson’s disease. The method of analysis is interactional phonetics. Results: Examples of discourse repetition are presented with accompanying interactional and phonetic analysis. The speaker is seen to produce the same linguistic tokens with varying phonetic features. In some cases, this variation means the tokens are realized as markedly different phonetic forms. Discussion: The results highlight how variable a single speaker’s realizations of the same word can be within a single conversation. Given this, it is proposed that intelligibility is best conceptualized as a range rather than as a single, invariant score.