How do children with developmental language disorder extend novel nouns?

In this study, we investigated the ability of children with developmental language disorder (DLD) to extend nouns referring to different categories of novel objects. In a word extension task, we used several types of object entities (solid, animate, nonsolid, functional, and spatial relations) for which children needed to attend to diverse properties (shape, texture, role, or spatial relation) to decide category membership. We compared 15 school-aged children with DLD with typically developing (TD) children matched on either age or vocabulary. Our results indicate that children with DLD were impaired in extending novel words for nonsolid substances and relational objects, whereas age-matched TD children performed well for all object classes. Similar to children with DLD, TD children matched on language had difficulty in extending spatial relation categories. We also show that children with DLD needed more learning exemplars and relied more on shape-based information than TD children, especially for spatial configuration objects. Overall, our findings suggest that children are able to learn regularities between object properties and category organization and to focus on diverse features according to the object presented when extending novel nouns. They also provide clear evidence linking DLD to deficits in novel name generalization and word learning.