Biomedical subjects
Publications and source records attributed to Francisco Lacerda.
UNLABELLED: The clinical significance of patterns of deficits in semantic and phonological representations observed by Miniscalco et al. is discussed in light of an ecological approach to language development. CONCLUSION: Deficits in semantic representations reflect problems in capturing the core linguistic referential function and should be taken as serious early warning signals for language delay.
UNLABELLED: The study of developmental language disorders is discussed from an interdisciplinary perspective. It is argued that retrospective studies have provided valuable information on developmental language disorders that needs to be integrated into a theoretical model capable of capturing the basic mechanisms of language development. CONCLUSION: It is concluded that interdisciplinary and prospective studies and theoretical work are necessary to increase insight into developmental language disorders.
Previous studies of infants' babbling have reported contradictory results as to the extent and timing of discernible phonetic influences of the ambient language. In the present experiment, five experienced phoneticians were asked to listen for ambient language effects on vocalizations produced by American and Swedish 12- and 18-month-olds (with 8 children in each language and age group), and to motivate their decisions in terms of word or phonetic cue perception. Group results indicated that listeners did not perceive effects of ambient language on pure babbles for either of the two age groups, whereas a clear effect appeared in both age groups given a more liberal definition of babbling. This is taken to suggest that results of ambient language listening tests may depend crucially on judgments of vocalizations' word status. As compared to the group trends, listener responses to individual children's vocalizations did not indicate that a majority of either 12- or 18-monthers were sufficiently native-sounding to be reliably identified on the basis of ambient language. A closer analysis of listeners' use of phonetic cues indicated that one single phonetic property, the grave tonal word accent, was discerned by most listeners in vocalizations produced by the Swedish 18-monthers; this property was also discerned by one listener in vocalizations produced by Swedish 12-monthers. This result is consistent with the generally held belief in the primacy of tonal features in phonetic acquisition, and with experimental evidence indicating that Swedish mothers tend to enhance word accent contours in baby talk. In the final section of the paper, the results are discussed with a view to reconcile competing theories of babbling development, notably the 'babbling drift' and the 'independence' hypotheses.
We investigated temporal resolution of auditory perception (TRAP), verbal working memory, and speech perception in 15 children with language impairment (LI) in comparison with a control group of 99 typical children. A computerized two-choice test was used to assess these three abilities. No deficits in TRAP were found in the LI group, and the thresholds were similar for both study groups. It was interesting that the variability was high for both groups and that the control group's performance was poorer than reported in some previously published studies. There were significant differences in the two groups' performance on speech perception and verbal working memory. Working memory was the most sensitive of these two measures.