Linguistic modality includes necessity and possibility (Psbl), each with a situational (objective, fact-based) and an epistemic (subjective, speaker-specific) variant.[1] Situational possibility may refer to one of three options: (a) ability or skill (as in She can swim), (b) permission (as in She is allowed to swim), and (c) objectively possible option (as in This is a lake one can swim in). This parameter considers the use of grammatical, rather than lexical, strategies for conveying situational possibility. These strategies — which may serve multiple functions in addition to expressing situational possibility — include verbal affixes, verbal constructions (including auxiliaries and serial verb constructions), and other markers, such as particles, adverbials, nouns, adjectives, and complex sentence structures.

Types:

NonSitPsbl: No grammatical strategies exist to express situational possibility.

SitPsblAff: Situational possibility is expressed through the use of verbal affixes. [2]

SitPsblV: Situational possibility is expressed through the use of verb constructions.

SitPsblNonaffNonV: Situational possibility is expressed through a strategy other than verbal affixes and verb constructions.[3]

When a language displays more than one strategy, multiple values can be listed. If one strategy is dominant, a slash (/) can separate the two values, with the dominant value appearing first; if neither is dominant, they are listed with an ampersand (&) separating the two.

[1] Example of epistemic possibility: She could be home now  (= I think it’s possible she is home now). Epistemic necessity: She should be home by now (= I’m nearly certain she’s home now). Situational necessity: One needs to breathe to stay alive.

[2] This value applies even if the use of verb affixes is not the only strategy available in the language for the expression of situational possibility.

[3] This should be detailed in the commentary.