Toddlers are sensitive to prosodic correlates of disfluency in spontaneous speech

The ability to distinguish fluent from disfluent speech could play an important role in infants’ acquisition of their first language. Across two experiments using a Headturn Preference Procedure, we show that infants are able to distinguish fluent from disfluent speech based on its prosodic characteristics, and show a preference for listening to fluent English. In the first experiment, 22-month-old, but not 10month-old, infants preferred to listen to fluent adult-directed speech samples over disfluent matched speech samples. In the second experiment, lexical and grammatical information were removed. Older infants still discriminated fluent from disfluent speech, but showed the reverse preference, for disfluent speech.