Languages vary in the syntactic means used to express the relationship between one's own thoughts and the thoughts, beliefs and utterances of others. For example, where some languages will use embedded clauses to report a belief or thought ("I think that Mary is here"), other languages use particles or verbal suffixes. A growing body of work in child language acquisition and psychology suggests that children differ from adults in their understanding of the thoughts and beliefs of others, that is, they are said to lack "Theory of Mind" before a certain age. Recently, a striking correlation has been found between the acquisition of the core properties of Theory of Mind and the acquisition of syntactic embedding. Professors Speas, Roeper, deVilliers, Garfield and Parsons-Yazzie are using recent advances in the study of linguistic embedding and Theory of Mind as a window into the triggers for the development of the understanding of other minds. In concert with their acquisition studies, they are investigating cross-linguistic differences between English, Tibetan and Navajo in several sub-systems of grammar whose interpretation requires integrating multiple epistemic perspectives. The results of their fieldwork feed the acquisition studies and are also being used to develop new pedagogical materials for teaching these subtle aspects of grammar to young Navajo students who are trying to learn and preserve their language.
