Language without Sound
Deaf people obviously cannot perceive the spoken word. Yet they do learn a language, one that involves a complex system of gestures. In the United States, the deaf usually learn American Sign Language (ASL), but many other sign languages also exist. Plainly, then, language can exist in the absence of sound. Are these gestural systems genuine languages? One indication that they are is that these systems are not derived by translation from the spoken languages around them but are independently created within and by communities of deaf individuals (Klima et al., 1979; Senghas, 1995). Further evidence comes from comparing the structure and development of ASL to that of spoken languages. ASL has hand shapes and positions of which each word is com-posed, much like the tongue and lip shapes that allow us to fashion the phonemes of spoken language (Stokoe, 1960). It has morphemes and grammatical principles for combining words into sentences that are similar to those of spoken language (Supalla Newport, 1978). Finally, babies born to deaf users of ASL (whether or not the babies themselves are deaf ) pick up the system from these caregivers through informal inter-action rather than by explicit instruction, just as we learn our spoken language (Newport & Ashbrook, 1977). And they go through the same steps on the way to adult knowledge as do hearing children learning English. Thus, language does not depend on the auditory-vocal channel. When the auditory modes of communication are denied to humans of normal mentality, they come up with an alternative that repro-duces the same contents and structures as other language systems. It appears that lan-guage is an irrepressible human trait: Deny it to the mouth, and it will dart out through the fingers.