"When deaf infants are raised by signing parents, they learn sign language in the same way that hearing infants learn spoken language. But deaf children who are not born to deaf parents – the majority of deaf children – often have no access to sign language users as they grow up, and indeed are sometime deliberately kept from them by educators in the “oralist” tradition who want to force them to master lip readhing and speech. (Most deaf people deplore these authoritarian measures.) When deaf children become adults, they tend to seek out deaf communities and begin to acquire the sign language that takes proper advantage of the communicative media available to them. But by then it is usually too late; they must then struggle with sign language as a difficult intellectual puzzle, much as a hearing adult does in a foreign language classes."
From The Language Instinct by Steven Pinker
