If your kid gets diagnosed with autism they get a government disability check every month.
Subsidize something and you get more of it.
However when you have a child who is non-verbal and they are over five you have a problem.
Occasionally you just have what is known as a "late talker" where the child will be none verbal and then suddenly start talking, often in complete sentences. But that is not the way to bet.
About a quarter of children who are autistic are non-verbal.
Something is badly wrong.