The Acquisition of Evidentiality and Source Monitoring

Evidential markers encode the source of a speaker’s knowledge. While some languages express evidentiality by lexical markers (e.g. I saw that it was raining vs. I heard that it was raining), about a quarter of world’s languages grammaticalize evidentiality through specialized markers. For instance, Turkish obligatorily marks all instances of past reference with one of the following two suffixes: -DI (the neutral form, which denotes the past of direct experience and is realized as –di, -dı, -du, -dü, -ti, -tı, -tu, -tü depending on the vowel harmony) and –mIş (which denotes the past of indirect experience and is realized as -miş, mış, -muş, -müş depending on the vowel harmony). As part of their evidential function, the morpheme –DI is used to describe witnessed events and the morpheme –mIş is used to describe non-witnessed events, i.e. knowledge acquired from someone else’s report (hearsay) or some clue (inference):