Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Medical Sciences (Growth and Development)


Linda Siegel


With advances in neonatal intensive care, many infants born at risk due to very low birthweight (1500 grams or less), due to intrauterine growth retardation (the small-for-gestational age infant has a birthweight less than 2 SD below the mean for gestation) or due to severe Respiratory Distress Syndrome and birth asphyxia, survive free of major debilitating sequelae. However, these apparently 'healthy' children may experience difficulties in perceptual, cognitive and academic performance. The early language development of 12 'healthy' children potentially at risk due to their pre- and perinatal histories, and a group of comparison children matched for sex and social class was investigated. Their language was recorded at home at three monthly intervals during a rapid phase of acquisition (18 to 30 months), to determine whether the two populations were acquiring language similarly. Of further interest was the ambient linguistic environment provided by their mothers. The language measures, derived from the child's spontaneous speech, quantified verbal output (rate and amount of speech), syntactic complexity (mean length of utterance, upper bound and type-token ratio) and morphemic acquisition. Comprehension and expressive scores were also derived from the Reynell Language Scales. The mothers' speech was scored for verbal output and syntactic complexity. The high risk children were as verbose as the comparison children, but their language was syntactically less complex. Their comprehension scores were also significantly lower. Although the high risk scores (uncorrected for the degree of prematurity) were within normal range, they were still significantly below those of the comparison children. This, along with the fact that the language of the two groups of mothers did not differ, and the fact that social class was not a significant factor, supports the position that maturational delay and/or cortical lesion may affect language acquisition. Other issues discussed included the propriety of applying a correction for prematurity to the results, and whether the results are evidence of a developmental lag, or a continuing disability likely to affect other emerging skills. Finally, this study provided correlations between language measures derived from spontaneous speech, and those from standardised language scales.

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