American Sign Language phonology

Sign languages such as American Sign Language (ASL) are characterized by phonological processes analogous to, yet dissimilar from those of oral languages. Although there is a qualitative difference from oral languages in that sign-language phonemes are not based on sound, and are spatial in addition to being temporal, they fulfill the same role as phonemes in oral languages.

Basically, three types of signs are distinguished: one-handed signs, symmetric two-handed signs (i.e. signs in which both hands are active and perform the same or a similar action), and asymmetric two-handed signs (i.e. signs in which one hand is active [the 'dominant' or 'strong' hand] and one hand is held static [the 'non-dominant' or 'weak' hand]). The non-dominant hand in asymmetric signs often functions as the location of the sign. Almost all simple signs in ASL are monosyllabic.

Signs consist of units smaller than the sign. These are often subdivided into parameters: handshapes with a particular orientation, that may perform some type of movement, in a particular location on the body or in the "signing space", and non-manual signals. These may include movement of the eyebrows, the cheeks, the nose, the head, the torso, and the eyes. Parameter values are often equalled to spoken language phonemes, although sign language phonemes allow more simultaneity in their realization than phonemes in spoken languages. Phonemes in signed languages, as in oral languages, consist of features. For instance, the /B/ and /G/ handshapes are distinguished by the number of selected fingers: [all] versus [one].

Most phonological research focuses on the handshape. A problem in most studies of handshape is the fact that often elements of a manual alphabet are borrowed into signs, although not all of these elements are part of the sign language's phoneme inventory (Battison 1978). Also, allophones are sometimes considered separate phonemes. The first inventory of ASL handshapes contained 19 phonemes (or cheremes, Stokoe, 1960). Later phonological models focus on handshape features rather than on handshapes (Liddell & Johnson 1984, Sandler 1989, Hulst, 1993, Brentari 1998, Van der Kooij 2002).

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