7.3 Hands

Hands are the most prominent articulators of Sign Language, and have many degrees of freedom and articulatory possibilities. They are represented in SignWriting with complex graphemes which encode in their graphical attributes the different features of the hand. In the corpus they are assigned the CLASS=HAND, and all four other tags are used: SHAPE, VAR, ROT and REF.

7.3.1 SHAPE

The first feature of the hand is its “shape” or configuration: how the fingers are bent and placed to form a unique shape that acts as a unit. Graphically, the SHAPE tag is roughly the outline of the grapheme, mainly the strokes representing the fingers. Fingers are very flexible, so there are a great many possible configurations that the hand can adopt, and SignWriting strives to provide symbols for every one of them. However, not all of them are in use in every sign language. There is also allophonic variation, meaning some different finger configurations are perceived to be the same hand shape for native signers, and so there can be vacillation and inconsistencies in their transcription.

In this corpus, hand shapes are labelled according to the phonology of Spanish Sign Language, not phonetically, so some different symbols are tagged with the same SHAPE. The phonological base for our labeling is to be published in a forthcoming article. Since there is not a standard notation for hand shapes across languages, we use our own ASCII-based notation which is derived from the previously mentioned phonology. For users not interested in the underlying linguistic theory, these labels can be assumed to be arbitrary strings uniquely identifying the different configurations. Currently, 72 different hand SHAPEs can be found in the corpus.

7.3.2 VAR

Apart from finger configuration, hands can rotate in the three dimensions of space, which complicates their transcription in the flat page. SignWriting uses a combination of graphical features to represent hand orientation, encoded in the remaining tags for hands in this corpus.

The first of them is the VARiation. Graphically, it encodes the “alteration” of the basic shapes encoded in the previous label. This variation can happen in two ways. First, the body of the hand can be filled with different patterns of black and white. White represents the palm, and black represents the back of the hand, as viewed from the point of view of the signer. The fingers can also be detached, meaning the orientation is horizontal.

Fill variation is encoded with the letters w (white), b (black), and h (half). Finger detachment is encoded by prepending the letter h (horizontal) to the tag. This gives six possible VAR tags:

There is also the possibility that a hand grapheme has a “black left” and “white right” fill pattern. This is encoded as h or hh, and treated as a graphical reflection (see below for the REF tag).

7.3.3 ROT

To complete the graphical representation of hand orientation, HAND graphemes can also be rotated around their center. This rotation is not continuous but rather has 8 possible values, encoded in this corpus using the notation for the cardinal directions. The hand is considered to be pointing along is distal axis, that is, the straight line from the forearm to the fingertips when they are fully extended.

7.3.4 REF

As a last transformation, HAND graphemes can appear “mirrored” in SignWriting. Mirroring of a grapheme is not reflective of any one phonological feature, but rather a graphical attribute that can be used to convey different meanings. For example, right and left hands are mirror images, so the corresponding graphemes can be mirrored to better identify each of them. “Black” VARiants are also often mirrored, to better iconically depict the hand as it would be seen by the signer.

Therefore, the meaning of reflecting a grapheme has to be extracted from the context, and can not be deduced from the isolated grapheme at all. This also means that there is not a phonological criterium to decide on a “normal” form of a grapheme, so the criteria chosen in this corpus may seem arbitrary. However, they are chosen to maximize graphical homogeneity and predictability, which can help in the computational treatment of SignWriting.

Reflection is codified in the REF tag, which can take the values n (not reflected) or y (“yes”, reflected). To decide whether an instance is reflected, the following algorithm is used:

1. Always, reflection must be decided from “North’ rotation. If a grapheme is rotated, it must first be (mentally) set upright.
2. If the VAR is h or hh, the variant with the black on the right is n, and the one with black on the left is y.
3. If the VAR is w or b, attention must be paid to the fingers. If they are in the same position as the unreflected h VARiant, then they are themselves not reflected. In other words, the h VARiant decides, and the b and w ones copy it.
4. If the w o b VARiant is not identical to the h one, attention is paid to the flexion of the fingers. If they bend to the left, the REF is n, otherwise it is y. In the case of the single little finger SHAPE, where the finger bends to one side but curls to the other, the not reflected grapheme is that where the finger is to the far left (white right hand). This step can also help decide the REF for other w or b graphemes without having to look up the h version.
5. Horizontal VARiants follow the same pattern as vertical ones.

The algorithm above is also important because when dealing with handwritten SignWriting, such as this corpus does, there can often appear “non-normative” uses of graphemes which are however understandable and need to be annotated. In any case, since pictures convey graphical information better than words, the following tables present some examples of REF tags.

7.3.5 Ambiguous graphemes

Sometimes grapheme SHAPEs are symmetric, meaning that the REFlected versions end up being graphically identical. In this case, REF is always taken to be n. In a few cases, rotation can also be ambiguous (for example the closed fist, which is a square). In this case, the first possible ROT in this sequence is chosen:

N\(\to\)NE\(\to\)E\(\to\)SE