Making Object Shape Explicit for Toddlers With Late Language Emergence.

Purpose Toddlers with late language emergence have difficulty acquiring an object vocabulary that is well defined by shape early in development. Without object words, subsequent language growth is delayed. The current study tested an intervention scaffold that highlights object shape during word teaching so that toddlers with late language emergence may establish themselves in the early stages of object word learning. Method Four toddlers with late language emergence participated in a brief dose of two interventions that differed only in semantic scaffold-a co-speech shape gesture or a co-speech indicator gesture. Co-speech refers to the word model and gesture occurring simultaneously. Shape gestures explicitly conveyed object form, whereas indicator gestures directed attention to the object. A single-subject experimental design tracked naming of taught objects and untaught exemplars. The study compared the mean number of phonemes produced in names between conditions. Results The four participants (a) extended more names to novel exemplars, (b) named more exemplar types, and (c) named more exemplar tokens when learned with shape gestures than with indicating gestures. The shape gesture advantage was confirmed with "percentage of nonoverlapping data" analysis. Not only did the shape gesture increase naming over the indicator gesture but more sounds were also mapped on average in the shape condition. Conclusion The current study used a semantic approach to the word learning problem in toddlers with late language emergence. We conclude that co-speech shape gestures led to semantic enrichment and facilitated phonological binding of the word representation. Future experiments should focus on a component analysis in parent-implemented interventions for greater carryover in the child's natural environment (i.e., external validity).