Epistemic modality conveys meanings that are related to the signer’s attitude towards the truth of a proposition based on his or her knowledge and it evaluates the probability of the event expressed in that utterance. In LSC, as well as in many other languages, some deontic markers are also used with an epistemic reading. For instance, the sign must-0 combined with specific mouthing /seguro/, is used to express the certainty of a proposition.
a) for_sure
b) yesterday argue_rec, today there_be_not for_sure angry.
‘We argued yesterday, so today he/she didn’t come because he/she must be angry.’
The verb seem, instead, is used to express a lower degree of certainty over a proposition. In the example below, the signer deduces that it is going to be sunny, since the clouds are disappearing in the sky; however, he is not a hundred per cent certain about it.
seem sun
‘It seems that it will be sunny.’
Some adverbs are also used to express epistemic modality in LSC. The adverb possibly/can is expressed with the same manual sign used for can plus specific non-manual markers: raised eyebrows, chin up, head tilt towards the ipsilateral side.
a) possibly/can
b) exam pass possibly/can.
‘Maybe he/she passes the exam.’
The adverb maybe is expressed with the same manual sign used for be_able plus again specific non-manual markers: raised eyebrows, chin up, head tilt towards the ipsilateral side.
a) maybe
b) tomorrow rain maybe.
‘Maybe it rains tomorrow.’
It seems then that in both adverbs, possibly/can and maybe, the epistemic meaning of uncertainty is encoded by the non-manual markers.
There are also some adjectives in LSC that express epistemic modality. For instance, the adjectives clear and evident are used to express certainty.
a) clear
b) exam copy clear.
‘It is clear that he/she copied in the exam.’
c) evident
d) exam ix evident copy ix-b.
‘It is obvious that he/she copied in the exam.’