New measures to chart toddlers' speech perception and language development : a test of the lexical restructuring hypothesis

Language acquisition factors at work in toddlers between 2 1/2 and 3 years of age were investigated in the first longitudinal study of this kind. New age-appropriate tasks were devised to measure the development of vocabulary size; articulation accuracy; sensitivity to the phonemic features of, in this case, Australian English; and the degree of specialisation towards the native tongue, as measured by language-specific speech perception; LSSP, with 45 Australian English learning toddlers (18 male, 27 female) at 30, 33, and 36 months of age. Results indicated (i) that nearly all measures improved linearly over age; (ii) that there were significant correlations between articulation ability and vocabulary size; and (iii) that, in confirmation of the lexical restructuring hypothesis, vocabulary size is significantly predicted by the broad range of native language abilities under the rubric of Phoneme Sensitivity, but not by the more specific measure of LSSP.