The influence of child-based factors and parental inputs on expressive language abilities in children with autism spectrum disorder.

Language impairment is one of the early signs of Autism Spectrum Disorder (ASD) that alerts parents to take their children for early diagnosis and intervention. Little is known about how children's autism traits, IQ, initial language abilities and parental inputs influence their language abilities. In addition, only a few studies have compared the relative influence of these factors. The present study addressed these issues by examining the structural language in parent-child spontaneous interactions. Forty-two Cantonese (Chinese)-speaking autistic children aged four to eight were recruited. Their expressive language skills grew rapidly more than 9 months, but their development trajectories varied. Initial expressive language ability is the only significant predictor of child language outcomes and language growth trajectories. In contrast, nonverbal cognition, autism traits, and parents' input do not affect language outcomes in children with ASD. Therefore, early language intervention is crucial for autistic children at all severity and IQ levels.