The dual form signals that two entities are involved. In most of the cases the dual is expressed by using numerals [Lexicon 3.10], determiners [Lexicon 3.6] or pronouns [Lexicon 3.7]. But verbs sometimes mark dual by either (i) reduplication or (ii) adding the non-dominant hand in case of a one-handed sign.
In the example below, the agreement verb give_as_present is reduplicated to express the dual form. Since give_as_present is a two-handed sign in DGS, it moves from a location in front of the signer’s body towards the addressee and is reduplicated the same way by starting again in front of the signer’s body.
professor3a study3b study3c person3b person3c book 3agive_as_present3b3agive_as_present3c
‘The professor gives a book to each of the students.’
(based on Happ & Vorköper, 2006: 203)
If the verb is a one-handed sign, the non-dominant hand can be added as illustrated below. Give is a one-handed agreement verb in DGS and normally articulated by the dominant hand. To make clear, that two objects are given, the non-dominant hand can be added and realizes the verb simultaneously.
dominant hand: eva3a marc3b bottlec bottled cl(/):‘3agive3b’
non-dominant hand: cl(/):‘3agive3b’
‘Eva gives Marc two bottles at the same time.’
(based on Happ & Vorköper, 2006: 202)