Purpose: Recent work suggests that speech perception is influenced by the somatosensory system and that oral sensorimotor disruption has specific effects on the perception of speech both in infants who have not yet begun to talk and in older children and adults with ample speech production experience; however, we do not know how such disruptions…

Infants born after fetal growth restriction (FGR)--an obstetric condition defined as the failure to achieve the genetic growth potential--are prone to neurodevelopmental delays, with language being one of the major affected areas. Yet, while verbal comprehension and expressive language impairments have been observed in FGR infants, children and…

Purpose: Gradual and sudden perturbations of vocal fundamental frequency (f[subscript o]), also known as adaptive and reflexive f[subscript o] perturbations, are techniques to study the influence of auditory feedback on voice f[subscript o] control mechanisms. Previous vocal f[subscript o] perturbations have incorporated varied setup-specific…

This dissertation examines how listeners' knowledge of interspeaker variability guides their generalization of perceptual learning in multi-talker listening. A series of perceptual learning experiments are conducted to evaluate whether listeners generalize what they have learned about a previous talker's production of sibilants and stop VOT to…

Recent findings have revealed that very preterm neonates already show the typical brain responses to place of articulation changes in stop consonants, but data on their sensitivity to other types of phonetic changes remain scarce. Here, we examined the impact of 7-8 weeks of extra-uterine life on the automatic processing of syllables in 20 healthy…

Purpose: Previous studies of speech articulation have shown that individuals who can perceive smaller differences between similar-sounding phonemes showed larger contrasts in their productions of those phonemes. Here, a similar relationship was examined between the perception and production of breathy voice quality. Method: Twenty females with…

Background: Articulatory excursion and vocal intensity are reduced in many children with dysarthria due to cerebral palsy (CP), contributing to the children's intelligibility deficits and negatively affecting their social participation. However, the effects of speech-treatment strategies for improving intelligibility in this population are…

We developed a computerized audiovisual training programme for school-aged children with specific language impairment (SLI) to improve their phonological skills. The programme included various tasks requiring phonological decisions. Spoken words, pictures, letters and written syllables were used as training material. Spoken words were presented…

Seeing articulatory gestures enhances speech perception. Perception of auditory speech can even be changed by incongruent visual gestures, which is known as the McGurk effect (e.g., dubbing a voice saying /mi/ onto a face articulating /ni/, observers often hear /ni/). In children, the McGurk effect is weaker than in adults, but no previous…

This dissertation begins with the observation of a typological asymmetry within phonological patterns related to phonetic naturalness. Patterns that are rooted within existing tendencies of perception and/or production--in other words, patterns that are phonetically "natural"--are common in phonological typology and seen in a variety of…

Previous research has argued that fundamental frequency is a critical component of phonetic accommodation. We tested this hypothesis in an auditory naming task with two conditions. Participants in an Unfiltered Condition completed an auditory naming task with a single male model talker. A second group of participants was assigned to a Filtered…

Combining information from the visual and auditory senses can greatly enhance intelligibility of natural speech. Integration of audiovisual speech signals is robust even when temporal offsets are present between the component signals. In the present study, we characterized the temporal integration window for speech and nonspeech stimuli with…

Speech production is inextricably linked to speech perception, yet they are usually investigated in isolation. In this study, we employed a verbal-repetition task to identify the neural substrates of speech processing with two ends active simultaneously using functional MRI. Subjects verbally repeated auditory stimuli containing an ambiguous vowel…

The phonological processes known as "lenition" have traditionally been explained as articulatory effort reduction. However, such a motivation for lenition has never been directly demonstrated; in addition, there are reasons to doubt the articulatory explanation.This paper focuses on a particular type of lenition (intervocalic…

Audiovisual speech perception was studied in adults with Asperger syndrome (AS), by utilizing the McGurk effect, in which conflicting visual articulation alters the perception of heard speech. The AS group perceived the audiovisual stimuli differently from age, sex and IQ matched controls. When a voice saying /p/ was presented with a face…