In adversative coordination, differently from conjunction and disjunction, the manual sign but can sometimes be obligatory. In contrastive adversative coordination it is optional (see (a) and (b)).
ht-right re, sq ht-left, bl-left ht-right, bl-left
a) giorgia cake chocolate very good but [fruit cl (5): ‘fruits’+++ burn][ipsi].
‘Giorgia baked a very good chocolate cake, but burnt a fruit cake.’
(© Alexandra Navarrete-González & Giorgia Zorzi 2019. Reprinted with permission from Navarrete-González & Zorzi, 2019)
b) giorgia [cakea chocolate very good][ipsi] [fruit cl (5): ‘fruits’+++b burn][contra].
‘Giorgia baked a very good chocolate cake (but) burnt a fruit cake.’
(© Alexandra Navarrete-González & Giorgia Zorzi 2019. Reprinted with permission from Navarrete-González & Zorzi, 2019)
In corrective adversative coordination it is optional, too, as in examples (a) and (b) below.
re hs re, ht-b
ht-right ht-right
a) jordi beer cl: ‘drink’ not but sangria yes.
‘Jordi did not drink beer but sangria.’
(© Giorgia Zorzi 2018. Reprinted with permission from Zorzi, 2018b: 139)
re hs bl-right
b) [marina room study not][contra] [ix-(loc) garden play][ipsi].
‘Marina is not studying in her room, she is playing in the garden.’
(© Giorgia Zorzi 2018. Reprinted with permission from Zorzi, 2018b: 138)
In counterexpectational adversatives, instead, its absence would cause a lack of contrast between the two conjuncts. The sentence in (a) below is an example which does not encode the same adversative meaning as (b). The non-manual markers cannot compensate for the missing manual marker.
re
bl-f
a) jordi very-tall but basketball play very-bad.
‘Jordi is very tall, but he is very bad at playing basketball.’
(© Giorgia Zorzi 2018. Reprinted with permission from Zorzi, 2018b: 107)
fe re bl-f
b) jordi very-tall. basketball play very-bad.
‘Jordi is very tall. He is very bad at playing basketball.’
(© Giorgia Zorzi 2018. Reprinted with permission from Zorzi, 2018b: 138)