The grammaticalization of evidentiality

[Extract] Evidentiality is a grammatical category with source of information as its primary meaning- whether the speaker saw the event happen (known as visual evidential), or heard it but didn't see it (non-visual evidential), or made an inference based on general knowledge or visual traces (assumed evidential and inferential evidential respectively), or was told about it (known as reported, secondhand, or hearsay evidential). Languages may distinguish just first-hand and non-first-hand information or have a special marker just for reported evidentiality. Non-first-hand evidential as a separate category typically covers inferential and reported meanings (but is not a subtype of either inferential or reported evidential). In larger evidential systems, first-hand or visual evidential may contrast with non-visual, inferred, assumed, and reported