The best approach to education for deaf children is bilingualism in ASL as their first language and English as their another language. A bilingual school for the deaf is much like a hearing child going to a bilingual school (e.g. French School, bilingual German school, and so on).
Abundant studies and observations show that the results are highly positive when deaf children have access to full-fledged ASL language, bilingual education (ASL and English), and positive, high self-esteem and identity.
Let's look at some Deaf children in ASL-English bilingual schools. First, the kindergarten.
It's so adorable. These Deaf children, whose first language is ASL, are much like my bilingual hearing child (coda), whose native language is ASL, the way they talk in ASL. E.g. "That's my favorite!" Pretty much typical.
Imagine a deaf child in a mainstream school. She/he may not have the same kind of equal socialization as seen in this video. Deaf children must have the equal human right for having a full access to full-fledged language, using their full language organs: visual articulators.
The brain doesn't tell the difference between two modalities (visual and auditory) for language acquisition and literacy development. Language is language for the brain regardless of the modalities, according to hard evidence in neuroscience. Having a native language (ASL), it's no harder for them to learn English than a bilingual hearing child (and each child is different and there may be other factors that play a different outcome). English literacy is not central to sound.
With language acquisition from birth and natural bilingual education, A Deaf adult without speaking or hearing at all can read and write English as fluently as a post-secondary hearing student.
You may also be interested in: schools for deaf children.