maria is a thirteen-year-old congenitally deaf child who was born to hearing parents living in a remote, rural area. since birth her parents have provided love, nourishment, educationally enriching toys, and developed their own hand signals to communicate with her about basic necessities. however, maria did not begin to learn sign language until she was twelve and the family moved to a city and encountered members of a deaf community. maria has found it very difficult to learn sign language, no matter what her instructors try. which of the follow concepts best explains maria’s difficulty learning sign language?