Word-learning abilities in deaf and hard-of-hearing preschoolers: effect of lexicon size and language modality.

Deaf and hard-of-hearing (DHH) children's ability to rapidly learn novel words through direct reference and through novel mapping (i.e., inferring that a novel word refers to a novel object) was examined. Ninety-eight DHH children, ranging from 27 to 82 months old, drawn from 12 schools in five states participated. In two tasks that differed in how reference was established, word-learning abilities were measured by children's ability to learn novel words after only three exposures. Three levels of word-learning abilities were identified. Twelve children did not rapidly learn novel words. Thirty-six children learned novel words rapidly but only in the direct reference task. Forty-nine children learned novel words rapidly in both direct reference and novel mapping tasks. These levels of word-learning abilities were evident in children who were in oral-only and in signing environments, in children with cochlear implants, and in deaf children of deaf parents. Children's word-learning abilities were more strongly correlated to lexicon size than age, and this relation was similar for children in these different language-learning environments. Acquisition of these word-learning abilities seems based on linguistic mechanisms that are available to children in a wide range of linguistic environments. In addition, the word-learning tasks offer a promising dynamic assessment tool.