LSC noun-verb pairs are mainly distinguished by a longer duration in the articulation of the sign in verbs in comparison to nouns. However, sometimes this difference is very subtle and there are some cases in which there is no difference at all. Moreover, there are other strategies that LSC uses to differentiate nouns and verbs that depend on the type of noun-verb pair we are looking at. We can organize these strategies in five different groups. Signs belonging to each group have some morphophonological characteristics in common that trigger the appearance of that specific type of strategy in order to differentiate the two categories:
1) Signs that do not have trajectory movement but a secondary movement (eg. broom, shower, scissors, flatware, ship, grandparent). In this group, nouns are articulated without a trajectory movement, but they display a repeated simple secondary movement. Verbs, instead, are articulated adding a trajectory movement.
a) broom
b) to_sweep
(recreated from Ribera, 2015: 106)
The fact that the trajectory movement is added in the verb leads also to a longer duration in the articulation of the verb compared to the noun.
2) Signs in which the noun has a simple movement that is reduplicated by the verb. Nouns in this group have a simple secondary movement and may have trajectory movement or not. Some examples of pairs in this group are food, car, expense, clothes, drawing, cook, comb, iron, among others.
a) comb
b) to_comb
(recreated fromRibera, 2015: 107)
A difference in duration in this group of signs is also attested between nouns and verbs, the verb having a longer duration.
3) Signs that reduplicate the secondary movement. In this group, the verb displays more repetitions in comparison with its noun counterpart. Many of the signs belonging to this group are body-anchored, but not all of them. Some examples are student, cook, debate, food, clothes, comb.
a) clothes
b) to_dress
(recreated from Ribera, 2015: 108)
4) Signs within this group display trajectory movement (or secondary trajectory movement). In this group, the difference between the noun-verb pair lies in the characteristics of the trajectory itself, namely, in the velocity of the execution of the sign and in the lengthening of the trajectory. Verb signs are articulated either more slowly or with a longer trajectory movement in comparison to nouns. Some examples in this category are coat, plane, desire, cat, dizziness, node, triumph, or ship.
a) plane
b) to_fly
(recreated from Ribera, 2015: 109)
5) Generally, signs belonging to this group are body-anchored, like for instance, wound, play, death, or surprise. However, among the signs in this group there are some that are not body-anchored like chair. In this group, no distinction in duration or repetition of the movement was found between the noun and the verb.
a) play
b) game
(recreated from Ribera, 2015: 110)
However, within this group, nouns display more mouthings than verbs. It is important to notice though that mouthing is also present in some of the verb counterparts [MORPHOLOGY 2.2.4].
Some of the noun-verb pairs may appear in more than one group of strategies (no more than two, though), because they allow for some phonological variation in the articulation of their movement (for instance, student, cook, debate, food, clothes, comb and ship).
In sum, regarding movement, verbs that add a trajectory movement or reduplicate the movement of the sign, have also a longer duration. So, there is a strong connection between movement and duration.
Regarding the duration of the sign, there is no difference between groups when we look at the type of noun (instrumental, concrete and abstract). In LSC thus the distinction between noun and verb is made primarily by the type of movement and not by the semantic type.
Nonetheless, regarding non-manual markers, mouthing is more present in concrete nouns than in abstract nouns, having the latter a bigger use of mouth gestures. As for verbs, a smaller percentage of them display mouthings, and a bigger percentage display mouth gestures in comparison to nouns. However, this is not always systematic. In group 5) verbs display more mouthings than in the rest of groups. In this group, though, the mouthing used for the verb is different than the one used for the noun. Namely, when articulating the verb, the mouthing displayed is the corresponding word for that verb in the closest spoken language (usually in Spanish). By contrast, when articulating the noun, the mouthing displays the corresponding word for the noun [MORPHOLOGY 2.2.4].
Other NMMs are also crucial in the distinction of some noun-verb pairs. In the pair chair-sit, for instance, the verb is articulated along with a backwards movement of the shoulders. In the pair grandparent-to_get_old, the verb is accompanied by a forward body lean. Lastly, in the pair coat-wrap_up_warm, the verb is expressed raising the elbows.