Evidential meanings in native and learner Japanese and English: Implications for the assessment of speaker certainty

Evidentiality is a linguistic category that comprises forms and meanings related to the source of information in utterances, the use of which may impact judgments about the degree of certainty expressed by a speaker. The main dichotomy is first-hand (direct) vs. second-hand (indirect) evidence. This distinction is grammaticalised in Japanese only, though certain related meanings can be expressed in English lexically or constructionally. The relevant forms in both languages also function as indirectness-for-politeness markers. We used a judgments elicitation task and found that statements with Japanese evidentials (both first- and second-hand) and with English markers of uncertainty lead to judgments of lower certainty than the statements without the evidential forms and meanings for the majority, but not for all speakers. In addition, monolingual and bilingual usage in both languages has parallels such that these two typologically distinct languages appear closer and certainty judgments by their speakers similar.