Knowing how we know: evidentiality and cognitive development.

Evidentials are grammatical elements such as affixes and particles indicating the source of knowledge. We provide an overview of this grammatical category and consider three research domains to which developmental studies on evidentiality contribute: the acquisition of linguistic means to characterize knowledge, the conceptual understanding of knowledge sources, and the evaluation of others' testimony. We also consider the study of evidentiality in relation to the Sapir-Whorf hypothesis about the influence of language on thought.