Evidentiality, discourse prominence and grammaticalization

This paper seeks to answer three questions: (1) What is the difference between grammatical and lexical indications of information source? (2) What qualifies an element for grammaticalization as an evidential? (3) How can we identify grammatical evidentials and instances of evidential grammaticalization? The answers proposed are as follows: (1) The difference between grammatical and lexical indications of information source is a difference between indications conventionalized as discourse secondary and indications conventionalized as potentially discourse primary. (2) A candidate for grammaticalization as an evidential must (i) have propositional scope, (ii) belong in the conceptual domain of information source, (iii) be frequent enough to pass the threshold for conventionalization, and (iv) be discourse secondary, but not by convention. (3) Grammatical evidentials and instances of evidential grammaticalization can be identified based on focusablity, addressability and modifiability.