Module 7 – Sign Phonetics and Phonology: Symmetry and Dominance Condition

As we have shown in previous modules, natural signs can be one-handed and two-handed. Two-handed signs may have different combinations of handshapes, locations and movements. Are the combinations entirely random? Are there any restrictions on these combinations? Are some forms more preferred than others? These are the questions we will discuss in this module. Below are some examples of two-handed signs in Hong Kong Sign Language. Can you classify them into several groups according to the handshapes and movements of the two hands? FLY-A-KITE, DIFFERENT-1, RUDE/AGRESSIVE, ADD, ELECTRICITY, DRIVE, WOOD, CABLE-CAR, SCIENCE, QUALITY, CONTROL/DIRECT, SOMETIMES, EQUIVALENT-TO, BUDDHA, DIFFERENT-2, JAPAN

Battison (1978, p.204) proposed that two-handed signs in ASL can be divided into three types: Type 1, Type 2 and Type 3. The same classification can actually be applied to HKSL (and other sign languages), too.

Type 1:

• Both hands are active and perform identical movements
• The hands may or may not contact each other/may or may not contact the signer’s body
• The movements may be synchronous or alternating.
  • Synchronous. This means the two hands perform the movements at the same time. Examples:
    • RESTRAINED-FEELINGS (ASL)
    • FLY-A-KITE (HKSL)
    • DIFFERENT-1 (HKSL)
    • EQUIVALENT-TO (HKSL)
    • RUDE/AGGRESSIVE (HKSL)
  • Alternating. This means the two hands alternate in performing the movement
    • WHICH (ASL)
    • DRIVE (HKSL)
    • SCIENCE (HKSL)
    • CONTROL/DIRECT (HKSL)

Type 2:

• In Type 2 signs, the two hands have the same handshape, but only one hand is moving. The active hand is called the dominant hand. The non-moving hand is known as the non-dominant hand or passive hand. Examples:
  • NAME (ASL)
  • ADD (HKSL)
  • DIFFERENT-2 (HKSL)
  • WOOD (HKSL)

Type 3:

• In Type 3 signs, only one hand is active, but the two hands do not share the same handshape. Examples:
  • DISCUSS (ASL)
  • JAPAN (HKSL)
  • ELECTRICITY (HKSL)
  • QUALITY (HKSL)
  • CABLE-CAR (HKSL)
  • SOMETIMES (HKSL)
  • BUDDHA (HKSL)

For Type 1 signs (i.e., signs in which both hands move), Battison observed that the two hands almost always have identical handshapes and movements. In fact, it is rather hard to find signs with two hands having different movements and handshapes.

You can try this yourself: sign BUS and ENJOY in Hong Kong Sign Language with your two hands simultaneously. The two signs have different handshapes, movements and locations:

1. Left hand: perform BUS, with fist, ipsilateral side, up and down movement
2. Right hand: perform ENJOY, with a Ḃ-handshape, circular movement on one’s chest.

Do you find it difficult to have two hands doing different actions simultaneously?

Based on his observations of Type-1 signs in ASL, Battison proposed The Symmetry Condition as follows (1978, p.33-35):

“The Symmetry Condition states that (a) if both hands of a sign move independently during its articulation, then (b) both hands must be specified for the same location, the same handshape, the same movement (whether performed simultaneously or in alternation), and the specification of orientation must be either symmetrical or identical.”

“Same location” means that the two hands are in the same area or they are in mirror-image locations on either side of the line of bilateral symmetry. “Symmetrical orientation” is defined as any orientation in which identical parts (any parts) of the two hands have mirror image orientation with respect to the plane which separates them. In the two-handed HKSL sign PROVE, the two hands are on the two sides of the midsagittal plane (the green dotted line), which is the vertical plane that separates the human body into the left and right halves. The ulnar sides (i.e., the side of the pinky finger) of the two hands are facing each other. Hence, this sign has a symmetrical orientation.

“Identical orientation” means that the two hands share the same orientation with the body, but it says nothing about the orientation of the hands with respect to each other (Battison 1978, p.33-35). Identical orientation can be illustrated by the HKSL sign WHAT-MONTH-WHAT-DAY, in which the palms of both hands are facing the signer’s body.

With regards to Type 3 signs, Battison made another interesting observation. While there is no restriction on the possible handshape of the active hand, the passive hand can only be one of the following handshapes: A, S, B, 5, G (i.e., 1), C and O, with very few exceptions. To account for this handshape asymmetry, Battison proposed the Dominance Condition (Battison, 1978, p.206). This condition states that (a) if the hands of a two-handed sign do not share the same specification for the handshape, then (b) One hand must be passive while the active hand articulates the movement, and (c) The specification of the passive handshape is restricted to one of a small set: A, S, B, 5, G (i.e., 1), C and O.

In effect, the Symmetry and Dominance Conditions exclude a large number of complex gestures from becoming possible signs in a sign language. The Symmetry Condition rules out signs that require two hands to perform different motor acts. The Dominance Condition requires that, if a two-handed sign has different handshapes, the overall complexity of the sign has to be reduced by prohibiting the movement of one hand, and severely restricting the possible handshape that can appear in the passive hand (1978, p.207). Out of the 45 possible handshapes in ASL, only 7 can appear as the passive hand of a Type-3 two-handed sign. These handshapes are unmarked handshapes – they are easier to articulate, more frequent within a sign language or across sign languages, and are mastered earlier by children who are acquiring sign language as their first language.

Although the Symmetry and Dominance Conditions were formulated for ASL lexical signs, these constraints appear to be universally valid in other sign languages as well (Channon, 2004). There are exceptions but they are relatively few in number. For example, in ASL and HKSL, 95.9%  and 87% of Type 3 signs adhere to the Dominance Condition. Channon (2004) argues that these two conditions actually reflect human beings’ cognitive and articulatory preference for signs to be simpler rather than being too complex.

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Module 8 – Sign Phonetics and Phonology: Phonological processes, lexical variation and historical changes >