Using a computer-based voice output communication aid (VOCA) device, the present study aimed to evaluate the effectiveness of augmentative and alternative communication systems for autistic symptoms, language features and emotion regulation of children diagnosed with autism spectrum disorders (ASD's). The child and adolescent psychiatrist (an experienced clinician) diagnosed the children as ASD according to Diagnostic and Statistical Manual of Mental Disorders fifth edition (DSM 5) and clinical observation and follow up. Forty-two children (36-72 months old) diagnosed with ASD participated in the study. Subjects were randomised into two groups (Twenty-one children were in the intervention group and 21 children were in the control group) and the first group received the augmentative and alternative communication systems treatment while the second received routine treatment. The socio-demographic features of groups were similar and children who were part of the experimental group showed improvements in receptive and expressive language skills, had better emotion regulation skills and their autistic symptoms decreased. Furthermore, the experimental group's mean length of utterance and language sample size increased. This study provided preliminary evidence that augmentative and alternative communication systems using computer-based voice output communication aids, which are portable and simple, may help children diagnosed with ASD develop communication and language skills.