Investigations of ASL from a linguistic point of view are a relatively recent phenomenon. Yet it has become clear that any feature that is characteristically found in spoken languages has a counterpart in ASL. All those defining properties of human language are present in ASL. There are equivalent levels of phonology and morphology (basic elements), as well as syntax (arrangements of those elements). For example, ASL uses Subject Verb Object (SVO) word order like English, but normally puts adjectives after nouns, unlike English (but like French).

Children acquiring ASL as their first language go through developmental stages similar to children learning spoken language, though the production of signs seems to begin earlier than the production of spoken words. In the hands of witty individuals, ASL is used for a wide range of jokes and “sign-play.” There are different ASL dialects in different regions and historical changes in the form of signs can be traced over the past hundred years (older versions are preserved on old films).

In summary, ASL is a natural language that is quite remarkable for its endurance in the face of decades of prejudice and misunderstanding. There is a very old joke among the deaf that begins with the question: What is the greatest problem facing deaf people? Perhaps increased knowledge and appreciation of their language among the general population will bring about a change in the old response to that question. The traditional answer was: Hearing people.