Some children with speech delays or speech problems have hearing loss. Obviously, if they were born with a hearing loss, they would never know anything different and couldn't tell you that they can't hear normally.
Your brain develops also by auditory input. If the child doesn't get adequate auditory input, as with a hearing loss, then the brain won't develop correctly. As with an auditory processing disorder. Not talking may well be a symptom of a hearing loss. It would be unwise to assume that the child will talk when they are "good and ready."
