A child born deaf will not be able to acquire English language as do hearing children. A hearing child will learn language subconsciously by hearing all the time. Deaf children do not learn language this way. Every word has to be taught individually by parents and teachers, and even this can only happen after the child has been convinced that language exists. This means that the child has to become aware that silent mouth movements mean something and the special movement of the hands are a way of communicating.
Many people believe the way to teach English to deaf children is via lip-reading.
This is difficult to learn and is easier if the individual already has a grasp of spoken language in the first place, so trying to teach a child who has not heard spoken language is more difficult. Some sounds are invisible, compare cat with at , hair with air. Many adult lip readers rely on visual and contextual clues, facial expression and a lot of guesswork. These are skills that a child is unlikely to have for some years. Understanding the written word will be difficult because there may not be any auditory memory of the words and the child has to rely on visual memory, this will make oral language difficult.