Commentary: what we can learn from research on evidentials.

Young children's well-documented difficulty reporting the sources of their knowledge, and their susceptibility to misleading suggestions about what they saw for themselves, might be reduced when their linguistic community expresses knowledge sources with grammatical evidential markers. Alternatively, until children have acquired certain cognitive prerequisites, they may interpret evidentials simply as markers of speakers' certainty. There is evidence supportive of both views, but with more precisely formulated research questions, specially tailored tasks, and more cross-linguistic comparisons, we can come to understand better the developmental intertwining of linguistic, metalinguistic, and cognitive aspects of children's handling of sources of knowledge.