The contrasting elements within these four general parameters can be analyzed into sets of features or primes. We say that “flat hand” is a prime in terms of shape and “palm up” is a prime in terms of orientation. Identifying each of these primes allows us to create a complete feature analysis of every sign in much the same way as we can analyze the phonological features of spoken language.

In addition to these parameters and primes, there are important functions served by non-manual components such as head movement, eye movement and several specific types of facial expressions. Under normal circumstances, THANK-YOU is articulated with a head nod and a smiling face. If a sentence is functioning as a question, it is typically accompanied by a raising of the eyebrows, widened eyes and a slight leaning forward of the head.

Also, if a new term or name is encountered, signers can use finger-spelling, which is a system of hand configurations conventionally used to represent the letters of the alphabet.

From these brief descriptions, it is clear that ASL is a linguistic system designed for the visual medium, in face-to-face interaction. The majority of signs are located around the neck and head. If a sign is made near the chest or waist, it tends to be a two-handed sign. One of the key differences between a system using the visual medium and one using the vocal-auditory channel is that visual messages can incorporate a number of distinct elements simultaneously. Spoken language production is linear, with one sound signal following another in time. In the visual medium, while signs are also produced linearly, multiple components can be produced at the same time in space.