In this study, infant vocabulary development was tracked in a multilingual society (Singapore) within a socioeconomically diverse sample. The sample comprised 1316 infants from 17.4 to 27.7 months (669 females, 647 males; 88% Chinese race, 4% Malay, 4% Indian, and 0.004% mixed-race [4% declined to provide race information]). Children varied in…

Although most studies of language learning take place in quiet laboratory settings, everyday language learning occurs under noisy conditions. The current research investigated the effects of background speech on word learning. Both younger (22- to 24-month-olds; n = 40) and older (28- to 30-month-olds; n = 40) toddlers successfully learned novel…

Early in development, many word-learning phenomena generalize to symbolic gestures. The current study explored whether children avoid lexical overlap in the gestural modality, as they do in the verbal modality, within the context of ambiguous reference. Eighteen-month-olds' interpretations of words and symbolic gestures in a symbol-disambiguation…

Presents data showing that the MacArthur Communicative Development Inventory's (CDI) large variability, lack of stability, and insufficient ability to predict early language delay are authentic reflections of individual differences in early language development rather than measurement deficiencies. Responds to critiques regarding sociodemographic…

Psychometric properties of the MacArthur Communicative Development Inventory (CDI) were examined. Findings suggested that the CDI reflects the progress of language development within the age range 10 to 27 months. Findings support caution in using results to identify individuals at risk for language deficits, to compare groups with different…