Language difficulties exert profound negative effects on the cognitive and social development of autistic children. Pivotal Response Treatment (PRT) is a promising intervention for improving social communication in autistic children, but there is a lack of a comprehensive examination of language functions. This study aimed to investigate the effectiveness of PRT in promoting the primary language functions (requesting, labeling, repeating, responding) defined by (Skinner, B. F. (1957). Verbal behavior. Martino Publishing.) theory of verbal behavior in autistic children. Thirty autistic children were randomly divided into the PRT group (M[subscript age] = 6.20, SD[subscript age] = 1.21) and control group (M[subscript age] = 6.07, SD[subscript age] = 1.49). The PRT group were provided with an 8-week training of the PRT motivation component in addition to treatment as usual (TAU) in their schools, whereas the control group only received TAU. Parents of the PRT group were also trained to practice the PRT motivation procedures at home. The PRT group demonstrated greater improvements in all four measured language functions compared to the control group. The improvement in language functions in the PRT group was generalized and maintained at the follow-up assessment. In addition, the PRT intervention enhanced untargeted social and communicative functioning, cognition, motor skills, imitation, and adaptive behaviors in the autistic children. In conclusion, language intervention using the motivation component of PRT is effective in promoting language functions as well as widespread untargeted cognitive and social functions in autistic children.