Although vocabulary size is thought to index children's language abilities, an increasing body of work suggests that regularities in children's vocabulary composition, particularly the proportion of shape-based nouns (e.g., cup), support language development. Here we examine initial vocabulary composition in children with hearing loss following cochlear implantation (n = 163) and age-matched children with normal hearing (n = 87). This comparison constitutes an experiment in nature for understanding how early vocabulary composition shapes subsequent language development in the context of the clinical provision of auditory experience. Children with higher initial proportions of shape-based nouns had larger vocabularies and scored higher on tests of receptive and expressive language abilities at 1, 2, and 3 years follow-up, than children whose vocabularies had lower proportions of shape-based nouns. These effects were strongest for cochlear implant users, especially 2-3 years postimplantation. The results suggest that knowing shape-based nouns facilitates language development and may ameliorate delayed language development trajectories.