What is "evidentiality"

n. (context linguistics English) The encoding into a language of the source of information being communicated, so as to distinguish (for example) hearsay from something actually witnessed.

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 terms such as mediative, médiatif, médiaphorique, and indirective used instead of evidential. Evidential is a meaning of nature and statement that is whether evidence exists for the statement and what kind of evidence exists.