Doctoral Dissertation Research: Disfluency Production and Comprehension in Children with and without Developmental Language Disorder

This doctoral dissertation project examines how children’s language abilities and experiences impact their production and comprehension of speech disfluencies. Speech disfluencies, including fillers 'uh' and 'um', are common in spontaneous language production and reliably precede difficult-to-retrieve words (e.g., words that are low-frequency or new to a conversation). Adults harness this association between fillers and production difficulty to anticipate upcoming novelty, but the mechanisms underlying children’s production and comprehension of fillers are poorly understood. This is particularly so for children who have Developmental Language Disorder (DLD) and/or are exposed to more than one language (bilingual children). The overarching goal of this proposal is to examine both production and comprehension of fillers in children with a range of language skills and experiences. The researchers measure children’s production of fillers in natural speech as well as measure their ability to understand disfluency in a listening task. Monolingual and bilingual school-aged children representing a full range of language ability (from DLD to typical language (TD)) participate in the studies. Across multiple studies, the researchers measure filler production in natural speech, manipulating task demands to elucidate the consequences for disfluency and investigate filler comprehension by monitoring children’s eye gaze during a listening task. Effects of language ability (TD vs. DLD) and bilingualism are examined continuously, through core language scores and years of language exposure. The project examines the factors that support filler use and comprehension, and it has implications for how speech practitioners measure and use disfluencies within clinical settings. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.