Fine-grained auditory discrimination and performance on tests of receptive vocabulary and receptive language

Spectral information in nonspeech contexts influences children's categorization of ambiguous speech sounds

For both adults and children, acoustic context plays an important role in speech perception. For adults, both speech and nonspeech acoustic contexts influence perception of subsequent speech items, consistent with the argument that effects of context are due to domain-general auditory processes. However, prior research examining the effects of context on children's speech perception have focused on speech contexts; nonspeech contexts have not been explored previously. To better understand the developmental progression of children's use of contexts in speech perception and the mechanisms underlying that development, we created a novel experimental paradigm testing 5-year-old children's speech perception in several acoustic contexts. The results demonstrated that nonspeech context influences children's speech perception, consistent with claims that context effects arise from general auditory system properties rather than speech-specific mechanisms. This supports theoretical accounts of language development suggesting that domain-general processes play a role across the lifespan.

Assessing speech perception in young children and relationships with language skills

Few materials are available to assess speech perceptual skills in young children without hearing impairments. However, children with a range of developmental conditions are at risk of speech discrimination deficits. Tasks that reliably assess speech perception skills are thus necessary for research and clinical practice. The development and application of two speech perception tests are described. Data were collected from 105 children, aged 4-5 years, attending mainstream schools, on two tasks, mispronunciation detection and non-word XAB, in quiet and in a background of multi-talker babble. Children's receptive language skills were also measured. Performance on mispronunciation detection was significantly better than on the XAB non-word task, and significantly better in quiet than in babble. Performance significantly improved with age, and speech discrimination was significantly related to receptive language abilities. Scores obtained in quiet and in babble were highly correlated and findings suggest there may be no advantage to testing in noise, except to avoid ceiling effects on performance. These tasks prove useful in the assessment of young children who may have speech discrimination deficits.

Sensory processing of backward-masking signals in children with language-learning impairment as assessed with the auditory brainstem response

The purpose of this study was to examine the possible contribution of sensory mechanisms to an auditory processing deficit shown by some children with language-learning impairment (LLI). Auditory brainstem responses (ABRs) were measured from 2 groups of school-aged (8-10 years) children. One group consisted of 10 children with LLI, and the other group (control) consisted of 10 children with normally developing language. The ABR was elicited with a brief tone burst presented either alone (no-masking condition) or immediately followed by a longer duration noise burst (backward-masking condition). The primary dependent variable was the latency of wave V of the ABR. The mean latencies were not significantly different for the 2 groups in the no-masking condition. However, in the backward-masking condition, the mean latency for the LLI group was significantly increased relative to the mean latency for the control group. Thus, the presence of successive sounds delay the neural response in children with LLI. The explanation for this delay at the level of the brainstem is not known, but it may be due to disruption of synchrony, activation of alternate (less direct) pathways, increased inhibition, or some combination of these (or other) factors.

Speech perception in children with specific reading difficulties (dyslexia)

Many experimental studies over the last two decades have suggested that groups of children who suffer significant delay in reading also show a weakness in phoneme discrimination and identification. In order to look further at the relation between type of reading deficit, auditory acuity, and speech discrimination, a group of 13 children with specific reading difficulty (SRD), 12 chronological-age controls, and 12 reading-age controls were tested on a battery of speech-perceptual, psychoacoustic, and reading tests. A sub-group of children with Specific Reading Difficulty (SRD) were poor at speech discrimination tests, whereas the rest of the SRD group performed within norms. For this sub-group, discrimination performance was particularly poor for consonant contrasts differing in a single feature that was not acoustically salient, and problems were encountered with nasal and fricative contrasts as wells with stop contrasts. These children did not differ from controls in their performance on non-speech psychoacoustic tasks. An evaluation is made of the reported phonemic awareness skills of beginning readers with regard to speech-processing issues which may help in understanding what factors are important in reading development.

Temporal resolution in infancy and subsequent language development

The MacArthur Communicative Development Inventory, a parent-report measure of vocabulary and syntax, was administered to 103 children (M = 23 months) who had participated in a study of temporal resolution when they were 6 months (n = 55) or 12 months (n = 48) of age. Children who performed above the median on the temporal resolution task in infancy were subsequently reported to have larger productive vocabularies, greater numbers of irregular word forms, and longer and more complex sentences than those who had performed below the median. Whether these findings reflect specific links between temporal resolution and language or whether they reflect general developmental factors remains to be determined.