The movement component (PHONOLOGY 1.3) plays a very important role in the articulation of signs because it determines the dynamic flow and allows the other formational parameters (handshape, orientation, and location) to change during the signing production. The importance of movement is also sustained by the observation that signs must include at least one movement. If they lack movement, they are considered ill formed. To repair an ill-formed sign, an epenthetic movement needs to be inserted (PHONOLOGY 3.2.1). Given the prominent role of movement in sign articulation, many scholars consider it as the nucleus of the sign syllable.
The syllable is defined as an intermediate prosodic unit between the phoneme and the foot. The number of syllables contained in a sign is determined on the basis of the number of sequential movements produced. If the sign contains one movement segment only, as life (a), it is considered a monosyllabic sign. Conversely, if it contains two movement segments, as live (b), it is considered a disyllabic sign.
a. life
b. live
Interestingly, the two examples above show a minimal pair of signs that are distinguished by syllable number only (one vs. two syllables).
The movement component also determines syllable weight. Like in other languages, in LIS, syllables can be of two types: light and heavy. A light syllable can be recognized by the presence of a simple movement, which can be a primary movement (a) (otherwise known as path movement, PHONOLOGY 1.3.1), or a secondary movement (PHONOLOGY 1.3.2), be it a handshape change (b) or an orientation change (c).
a. street
b. switch_on
c. open
These three examples count as monosyllabic signs, and each one includes one light syllable. On the other hand, a heavy syllable is characterised by a complex movement, which is defined as the simultaneous combination of two movements. In LIS, it is possible to combine: i) a path movement with a handshape change, as in copy (a), ii) a path movement with an orientation change, as in first_time (b), and iii) a handshape change with an orientation change, as in case (c).
a. copy
b. first_time
c. case
These three examples count as monosyllabic signs and each one includes one heavy syllable.
Syllables in LIS may also differ in terms of visual sonority. The degree of sonority depends on movement prominence, in particular on the kind of articulatory joint used to produce the movement. The closer the joint is to the signer’s body, the higher the sonority of the relevant syllable. For sign language syllables, the following sonority hierarchy has been identified: shoulder > elbow > wrist > base joints > non-base joints (from the most to the least prominent joint). To illustrate, we present five LIS signs, ordered from the highest to the lowest level of sonority: adult (shoulder), thank_you (elbow), spring (wrist), duck (base joints), and title (non-base joints).
a. adult
b. thank_you
c. spring
d. duck
e. title