Background: This study examined language development in young children with hearing loss and different types of additional disabilities (ADs). Method: A population-based cohort of 67 children who were enrolled in the Longitudinal Outcomes of Children with Hearing Impairment study took part. Language ability was directly assessed at 3 and 5 years of age using the Preschool Language Scale, Fourth Edition and the Peabody Picture Vocabulary Test, Fourth Edition. Standard scores were used to enable comparison with age-based expectations for typically developing children. Results: Analysis of variance showed that, across the total cohort, children's language scores remained stable over the 2-year period. However, this overall stability masked a significant difference between children with different types of ADs; in particular, children with autism, cerebral palsy and/or developmental delay showed a decline in standard scores, whereas children with other disabilities showed a relative improvement. In addition, larger improvements in receptive vocabulary were associated with use of oral communication only. Conclusions: The results suggest that type of AD can be used to gauge expected language development in the population of children with hearing loss and ADs when formal assessment of cognitive ability is not feasible.