A 4-year-old girl is evaluated in the child psychiatry clinic after her kindergarten teacher reported that she does not interact with other children, rarely speaks, and becomes distressed when her routine is disrupted. Her parents note that she has always been 'different' — she was slow to smile, did not point to objects of interest, and has never engaged in pretend play. She shows intense interest in spinning objects and becomes upset if her toys are not arranged in a specific order. Her developmental milestones were within normal limits, but her language is echolalic and she does not use words to communicate her needs. Intelligence testing shows average cognitive ability. Which of the following is the MOST appropriate initial management?