This paper reports a normative study on the phonological development of British English-speaking children. Speech samples of 684 children, aged between 3;0 and 6;11 years, randomly selected from nurseries and schools in eight different areas throughout the UK, were collected and analysed to obtain normative data. This paper reports on two aspects of speech development: the age of acquisition of sounds (phonetic acquisition) and the age that error patterns were suppressed (phonemic acquisition). It discusses the effects of age, gender and socio-economic status on speech sound development. The study found that older children had more accurate production and fewer error patterns in their speech. It found no gender differences in the younger age groups. However, in the oldest age group, it found the phonological accuracy measures of girls' better than boys. It found no significant effects of socio-economic status on any of the phonological accuracy measures.

Recent work on integration of auditory and visual information during speech perception has indicated that adults are surprisingly good at, and rely extensively on, lip reading. The conceptual status of lip read information is of interest: such information is at the same time both visual and phonological. Three experiments investigated the nature of short term coding of lip read information in hearing subjects. The first experiment used asynchronous visual and auditory information and showed that a subject's ability to repeat words, when heard speech lagged lip movements, was unaffected by the lag duration, both quantitatively and qualitatively. This suggests that lip read information is immediately recoded into a durable code. An experiment on serial recall of lip read items showed a serial position curve containing a recency effect (characteristic of auditory but not visual input). It was then shown that an auditory suffix diminishes the recency effect obtained with lip read stimuli. These results are consistent with the hypothesis that seen speech, that is not heard, is encoded into a durable code which has some shared properties with heard speech. The results of the serial recall experiments are inconsistent with interpretations of the recency and suffix effects in terms of precategorical acoustic storage, for they demonstrate that recency and suffix effects can be supra-modal.

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Little is known about the acquisition of phonology by children learning Cantonese as their first language. This paper describes the phoneme repertoires and phonological error patterns used by 268 Cantonesespeaking children aged 2; o to 6; o, as well as a longitudinal study of tone acquisition by four children aged 1 ;2 to 2;o. Children had mastered the contrastive use of tones and vowels by two years. While the order of acquisition of consonants was similar to that reported for English, the rate of acquisition was more rapid. The developmental error patterns used by more than 10% of children are also reported as common in other languages. However, specific rules associated with Cantonese phonology were also identified. Few phonological errors were made after age four. The results are consistent with the hypothesis that the ambient language influences the implementation of universal tendencies in phonological acquisition.

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Background: Children with speech disorder are a heterogeneous group (e.g. in terms of severity, types of errors and underlying causal factors). Much research has ignored this heterogeneity, giving rise to contradictory intervention study findings. This situation provides clinical motivation to identify the deficits in the speech-processing chain that underlie different subgroups of developmental speech disorder. Intervention targeting different deficits should result in a differential response to intervention across these subgroups. Aims: To evaluate the effect of two different types of therapy on speech accuracy and consistency of word production of children with consistent and inconsistent speech disorder. Methods & Procedures: Eighteen children (aged 4;08-6;05 years) with severe speech disorder participated in an intervention study comparing phonological contrast and core vocabulary therapy. All children received two 8-week blocks of each intervention. Changes in consistency of production and accuracy (per cent consonants correct) were used to measure the effect of each intervention. Outcomes & Results: All of the children increased their consonant accuracy during intervention. Core vocabulary therapy resulted in greater change in children with inconsistent speech disorder and phonological contrast therapy resulted in greater change in children with consistent speech disorder. Conclusions: The results provide evidence that treatment targeting the speechprocessing deficit underlying a child's speech disorder will result in efficient system-wide change. Differential response to intervention across subgroups provides evidence supporting theoretical perspectives regarding the nature of speech disorders: it reinforces the concept of different underlying deficits resulting in different types of speech disorder.

The McGurk effect, in which auditory [ba] dubbed onto [ga] lip movements is perceived as "da" or "tha," was employed in a real-time task to investigate auditory-visual speech perception in prelingual infants. Experiments 1A and 1B established the validity of real-time dubbing for producing the effect. In Experiment 2, 4 1/2-month-olds were tested in a habituation-test paradigm, in which an auditory-visual stimulus was presented contingent upon visual fixation of a live face. The experimental group was habituated to a McGurk stimulus (auditory [ba] visual [ga]), and the control group to matching auditory-visual [ba]. Each group was then presented with three auditory-only test trials, [ba], [da], and [(delta)a] (as in then). Visual-fixation durations in test trials showed that the experimental group treated the emergent percept in the McGurk effect, [da] or [(delta)a], as familiar (even though they had not heard these sounds previously) and [ba] as novel. For control group infants [da] and [(delta)a] were no more familiar than [ba]. These results are consistent with infants' perception of the McGurk effect, and support the conclusion that prelinguistic infants integrate auditory and visual speech information.

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