In 118 children followed from age 2 to 5 (59 with autism, 24 with PDD-NOS and 35 with non-spectrum developmental disabilities), age 2 and age 3 scores of non-verbal ability, receptive communication, expressive communication and socialization were compared as predictors of receptive and expressive language at age 5. Non-verbal cognitive ability at age 2 was generally the strongest predictor of age 5 language, while at age 3 communication scores were a stronger predictor of age 5 language for children with autism. Early joint attention as well as vocal and motor imitation skills were more impaired in children who did not develop language by age 5 (but had relatively strong non-verbal cognitive skills) than in children who did develop language by 5.