Özet:
In this thesis, modality is explored from different perspectives such as semantics, typology and psycholinguistics. The aim of this thesis is to investigate how modality unfolds in the linguistic development of Turkish children and to find what factors affect this development. This aim is accomplished with a longitudinal and an experimental study. In the longitudinal study, two Turkish children's production of modality between ages 1;3-2;0 and 1;6-2;10 is investigated. In the experimental study, children between ages 3 and 5 are tested on their ability to comprehend expressions of modality. Also, in these studies various influences on the acquisition of modality are investigated, such as child directed speech, multifunctionality of forms, morphological and lexical means of modal expressions, pragmatic functions and children's theory of mind abilities. The results of the longitudinal study suggest that the first modal category to be acquired is dynamic modality and then soon after evidential modality. Lastly, epistemic and deontic modalities are acquired around the same time. This is corroborated by the findings ofthe experimental study. Moreover, the influences on the acquisition of modality found on either study were child directed speech, multifunctionality of forms, means of mod ali zed expressions and theory of mind skills.
