It has its own rules that determine the meaning and significance of each gesture. Experts familiar with these rules can use their hands to communicate extremely complex thoughts. This paragraph is incomplete because the first two sentences merely state the topic. It satisfies only those readers who are already familiar with the intricacies of American Sign Language. But such readers would not even need this brief paragraph.
Adjectives follow nouns, as in Romance languages.
The movement of the shoulders, the speed of the hands, the facial expression, the number of repetitions of a sign, combine with the actual signs to give meaning to the language. Signing is precise. The casual gestures hearing people make when talking have no meaning in sign language. In some hands, signing is an art equal to an actor's rendering of Shakespeare. It is not just swoops and swirls but an enormous variety of expression, just as a great actor's delivery is completely different from some ham's idea of haughty speeches.