Manual markers of negation refer to instances of incorporation of a negative element within the articulation of the verb sign, which however remains identifiable. Incorporation can be either a sequential or simultaneous process. In sequential incorporation, the negative morpheme not, combines with the verb stem. This is illustrated for the verbs know (a), be_able (b) and want (c). The typical negative headshake (hs) occurring with the marker not can spread on the preceding verb stem.
hs
a. know^not
‘Do not know’
hs
b. be_able^not
‘(To) not be able’
hs
c. want^not
‘Do not want’
On the other hand, the modal can (see SYNTAX 1.5.1.1.2 for details) allows the simultaneous incorporation of the negative element not. As we can see from the example below, the sign for the modal can (a) is a symmetrical two-handed sign articulated with both hands closed in the neutral space, displaying a short movement downward. To convey the negative meaning, a left-to-right rapid movement is added, together with the typical negative non-manual marker. The resulting sign is can^not (b).
a. can
hs
b. can^not
‘Cannot’