Evidentiality is a grammatical mood that expresses the type of evidence on which the speaker bases a statement; it is marked grammatically by the use of affixes, auxiliary verbs or particles.[1]

Evidentiality may be direct or indirect. Direct evidentials are used when the speaker has first-hand evidence that the incident occurred. This evidence may be visual (seeing) or auditory (hearing).[2] Indirect evidentials are used when the speaker is not a first-hand witness.[3] Although use of evidentials occurs primarily for the present and past tense, it may also occur with the future tense as well as in questions. Some languages may restrict its use to the past tense.

This parameter considers only the existence of evidentiality as a grammatical category.

Types:

NoEvid: The language does not have a grammaticalized form to express evidentiality.[4]

DirEvid: A grammaticalized form exists to express direct evidentials.

IndEvid: A grammaticalized form exists to express indirect evidentials.

Evid: Grammaticalized forms exist to express both direct and indirect evidentials.

[1] Lexical strategies, such as using the adjunct supposedly or introducing a subordinate clause with they say, do not constitute grammatical strategies and are therefore not considered for this parameter.

[2] Some languages may use distinct forms for visual and auditory evidentials.

[3] Two subtypes of inferential evidentiality are (1) when the speaker infers the information based on current physical experience, and (2) when the speaker learns the information from others (also known as quotative or reportative evidentiality). Some languages may distinguish these two subtypes, while others treat the two identically.

[4] If this value applies to a language, it applies by default in the parameter Coding of evidentials.