All children, regardless of their hearing status, are by nature visual learners first throughout much of their childhood, and there is something unnatural about forcing young pre-lingually deaf children to rely largely on their imperfect and incomplete hearing to develop cognitively and linguistically during the critical period for language acquisition. Research by Dr. Laura Petitto of McGill University shows that the language function in infants and toddlers is not governed by speech processes. In other words, there is no difference between sign language and speech in terms of the early development of language function. Even then, having good speech in itself does not guarantee success. The Canadian Association of the Deaf correctly states that literacy itself is the key to successful functioning in a hearing world for the deaf person.
Literacy is a visual function.
There are two houses only about 10 yards apart from each other. The houses are HUGE, enough room for hundreds of people. Looking in the windows of one house you can see some people laughing and talking in a brightly lit room. Now you have the HOH people, outside between the two houses. That is how we HOH are made to feel on a regular basis by a fairly large portion of society - hearing AND Deaf alike.