A Grammar of Sign Language of the Netherlands (NGT)

Symmetrical (or balanced) signs are two-handed signs in which the hands take the same handshape, (mirrored) orientation, location and movement. According to Battison’s symmetry condition, signs in which both hands move independently, the handshapes, orientation and location must be identical. Signs in NGT adhere to this condition, in other words, the independent movement of two hands can only occur in symmetrical signs.

Three examples of symmetrical signs are shown in Figure 2.29. The sign christmas in Figure 2.29a is fully symmetrical, as both hands mirror each other and the movement is synchronous. plant in Figure 2.29b involves an alternating movement, but is still considered symmetrical. A small group of two-handed symmetrical signs does not show a mirrored orientation and movement, but consists of signs with two identical handshapes which, under continuous contact, move in the same direction. An example is standardization, shown in Figure 2.29c.

Figure 2.29. The symmetrical signs christmas (a), plant (b)and standardization (c) (Crasborn et al. 2020, symbols added).