7.2 Invariant Graphemes

Some graphemes of SignWriting are always represented upright and in the same orientation, namely HEAD and DIAC graphemes. In the case of HEAD, the body is normally assumed to be upright while signing, so it is drawn as such. When there are alterations to this principle, such as head movement, they are indicated with additional symbols rather than by transforming the grapheme. In the case of DIAC, these are abstract symbols with no internal spatial information, so are always represented with a constant, invariant shape (see their section for a caveat).

Therefore, HEAD and DIAC graphemes only use the CLASS and SHAPE tags in the corpus tag schema. The possible SHAPEs are enumerated in the following.

7.2.1 HEAD

HEAD graphemes represent the location of the sign relative to a number of different bodily locations in the head, and at the same time depict some of the non-manual parameters of the sign. In this corpus, this articulation is only annotated for the mouth. There rarely appear logograms with other marks, such as head or eye inclination, but it has not been annotated (for now).

In HEAD graphemes, the SHAPE tag specifies the holistic meaning of the full grapheme, including place of articulation and mouth gesture. Since HEAD graphemes are invariant, no other tags are used.

7.2.2 DIAC

DIAC graphemes are small, invariant marks, such as contact or dynamics marks or internal movements of the hand. They are classified as such due to their graphical characteristics, rather than after a thorough examination of whether they count as diacritics or not, or due to some internal semantic coherence of the class.

Their concrete meaning is codified in their SHAPE tag. While some are graphical transformations of each other, their rotation and reflection is not productive so ROT or REF tags are not used.

However, sometimes DIACs can appear rotated or reflected for stylistic reasons. This does not alter meaning, but it is important to distinguish between DIACs that are mirror one of the other, with different meanings, and DIACs that accept some stylistic variation to better convey location or what other graphemes they modify.