While previous research on language development has highlighted the facilitating role of gesture (mainly deictic gesture) in children’s early access to meaning, little is known about the possible facilitating role of prosody and also of co-speech gestures in children’s pragmatic development in the preschool years. Previous work on developmental pragmatics has focused on the acquisition of morphosyntactic and lexical forms, and there is a need to adopt a more integrative multimodal perspective. The overarching aim of this thesis is to experimentally investigate, through a set of cross-sectional studies with preschool children (3-to 5-year-olds), whether prosodic and gestural cues serve as pragmatic precursors in the development of two key pragmatic phenomena, namely knowledge state (ie, commitment to the status of information) and politeness (eg, broadly speaking, adjusting one’s language).