Filled Pauses Produced by Autistic Adults Differ in Prosodic Realisation, but not Rate or Lexical Type.

We examined the use of filled pauses in conversations between homogeneous pairs of autistic and non-autistic adults. A corpus of semi-spontaneous speech was used to analyse the rate, lexical type (nasal "uhm" or non-nasal "uh"), and prosodic realisation (rising, level or falling) of filled pauses. We used Bayesian modelling for statistical analysis. We found an identical rate of filled pauses and an equivalent preference of "uhm" over "uh" across groups, but also a robust group-level difference regarding the intonational realisation of filled pauses: non-autistic controls produced a considerably higher proportion of filled pause tokens realised with the canonical level pitch contour than autistic speakers. Despite the fact that filled pauses are a frequent and impactful part of speech, previous work on their conversational use in autism spectrum disorder (ASD) is limited. Our account is the first to analyse the intonational realisation of filled pauses in ASD and the first to investigate conversations between autistic adults in this context. Our results on rate and lexical type can help to contextualise previous research, while the novel findings on intonational realisation set the stage for future investigations.