Linguistic modality includes necessity and possibility (Psbl), each with a situational (Sit) and an epistemic (Ep) variant. Situational modality indicates that the described information is based on objective information, while epistemic refers to the speaker’s opinions.[1]

Some language use different strategies to express situational and epistemic modality, while others do not. Overlap between the two types may be partial or total. Partial overlap refers to the use of identical lexical or grammatical strategies[2] with distinctions in morphology or word order.

This parameter considers the degree of distinction between situational and epistemic necessity (deontic modality, Deon).

Types:

NoDeon: Necessity cannot be expressed through verbal modality.[3]

DeonSit=Ep: There is no distinction between situational and epistemic necessity in terms of verbal modality.

DeonSit~Ep: Situational and epistemic necessity are partially distinguished in terms of verbal modality.[4]

DeonSitNonEp:  Situational and epistemic necessity are totally distinguished in terms of verbal modality.

[1] Situational necessity refers to an objective need, such as War requires weapons, Everyone must die one day and A master’s degree is a prerequisite for application to the program. Epistemic necessity, on the other hand, refers to a need or requirement as determined by the speaker, such as The boy must be home by now.

[2] This may refer to the same auxiliary or the same affix, for example.

[3] This value applies to the expression of modality in a main clause containing a subordinate clause, as seen in examples such as It’s necessary that I... Such constructions do not constitute verbal modality, but rather logical modality, which is not addressed in this parameter.

[4] This should be detailed in the commentary.