In
linguistics,
evidentiality is, broadly, the indication of the nature of evidence for a given statement, that is, whether
evidence exists for the statement and/or what kind of evidence exists. An
evidential (also
verificational or
validational) is the particular
grammatical element (
affix,
clitic, or
particle) that indicates evidentiality. Languages with only a single evidential have had the terms
mediative,
médiatif,
médiaphorique, and
indirective used instead of
evidential.
All languages have some means of specifying the source of information. European languages (such as Germanic and Romance languages) often indicate evidential-type information through modal verbs (French devoir, Dutch zouden, Danish skulle, German sollen) or other lexical words (adverbials) (English reportedly) or phrases (English it seems to me).
Some languages have a distinct grammatical category of evidentiality that is required to be expressed at all times. The elements in European languages indicating the information source are optional and usually do not indicate evidentiality as their primary function — thus they do not form a grammatical category. The obligatory elements of grammatical evidentiality systems may be translated into English, variously, as I hear that, I see that, I think that, as I hear, as I can see, as far as I understand, they say, it is said, it seems, it seems to me that, it looks like, it appears that, it turns out that, alleged, stated, allegedly, reportedly, obviously, etc.
Many languages with grammatical evidentiality mark evidentiality independently from tense-aspect or epistemic modality (which is the speaker's evaluation of the information, i.e. whether it is reliable, uncertain, probable).
