16+ mth old (yet to say simple word)

Hi parent, My boy is going to be 17th mth old and yesterday we went to visit a pediatric for his vaccinations. She comment that my boy have some speech delay for the current month age he is in as he haven’t start to say out few simple word like mama , papa. And she also mentioned will monitor him again when he coming for another vaccination when he is 18th mth old , if he still don’t talk then she will arrange a therapist to assist in this issue. I find is normal even toddler hasn’t start talking... my girl start to call us when she is 2 yr old. Any comments/view to share?