Linguistic modality includes necessity (also known as deontic modality, abbreviated in the values as Deon) and possibility, each with a situational (objective, fact-based) and an epistemic (subjective, speaker-specific) variant.  Situational necessity may refer to one of three options: (a) general necessity (as in One needs to breathe to stay alive), (b) context-specific necessity (as in I need to take my medicine), and (c) requirement (as in A high school diploma is required to apply to college). Situational necessity can be expressed through the use of verbal affixes, verbal constructions (including auxiliaries and serial verb constructions), and other markers, such as particles, adverbials, nouns, adjectives, and complex sentence structures. These strategies may serve multiple functions, in addition to expressing situational necessity.
NonSitDeon: No grammatical strategies exist to express situational necessity.
SitDeonAff: Situational necessity is expressed through the use of verbal affixes.
SitDeonV: Situational necessity is expressed through the use of verb constructions.
SitDeonNonaffNonV: Situational necessity is expressed through a strategy other than verbal affixes and verb constructions.
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.
 Example of situational possibility: Swimming is allowed here. Example of epistemic possibility: She could be home by 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).
 This value applies even if the use of verb affixes is not the only strategy available in the language for the expression of situational necessity.
 This should be detailed in the commentary.